Dermatopathology

Celiac disease is a chronic, immune-mediated, systemic disorder caused by intolerance to gluten — a protein present in rye, barley, and wheat grains — that affects genetically predisposed individuals.

Due to its wide spectrum of clinical manifestations, celiac disease resembles a multisystemic disorder. Its most common gastrointestinal (GI) symptoms include chronic diarrhea, weight loss, and abdominal distention. However, celiac disease can also manifest in myriad extraintestinal symptoms, ranging from headache and fatigue to delayed puberty and psychiatric disorders, with differing presentations in children and adults.

To date, the only treatment is adopting a gluten-free diet (GFD). Although key to preventing persistent villous atrophy, the main cause of complications in celiac disease, lifelong adherence to GFD is challenging and may not resolve all clinical issues. These shortcomings have driven recent efforts to develop novel therapeutic options for patients with this disease.

Here are five things to know about celiac disease.
 

1. Rising Prevalence of Celiac Disease and Other Autoimmune Disorders Suggests Environmental Factors May Be at Play

Gluten was first identified as the cause of celiac disease in the 1950s. At that time, the condition was thought to be a relatively rare GI disease of childhood that primarily affected people of European descent, but it is now known to be a common disease affecting those of various ages, races, and ethnicities.

A 2018 meta-analysis found the pooled global prevalence of celiac disease was 1.4%. Incidence has increased by as much as 7.5% annually over the past several decades.

Increased awareness among clinicians and improved detection likely play a role in the trend. However, the growth in celiac disease is consistent with that seen for other autoimmune disorders, according to a 2024 update of evidence surrounding celiac disease. Shared environmental factors have been proposed as triggers for celiac disease and other autoimmune diseases and appear to be influencing their rise, the authors noted. These factors include migration and population growth, changing dietary patterns and food processing practices, and altered wheat consumption.
 

2. No-Biopsy Diagnosis Is Accepted for Children and Shows Promise for Adults

It is estimated that almost 60 million people worldwide have celiac disease, but most remain undiagnosed or misdiagnosed, or they experience significant diagnostic delays.

Prospective data indicate that children with first-degree relatives with celiac disease are at a significantly higher risk of developing the condition, which should prompt screening efforts in this population.

The 2023 updated guidelines from the American College of Gastroenterology (ACG) state that serology testing plays a central role in screening. This commonly involves serological testing for positive serological markers of the disease, including immunoglobulin A (IgA), anti-tissue transglutaminase IgA (tTG-IgA), anti-deamidated gliadin peptide, or endomysial antibodies.

To confirm diagnosis, clinicians have relied on intestinal biopsy since the late 1950s. The ACG still recommends esophagogastroduodenoscopy with multiple duodenal biopsies for confirmation of diagnosis in both children and adults with suspicion of celiac disease. However, recent years have seen a shift toward a no-biopsy approach.

For more than a decade in Europe, a no-biopsy approach has been established practice in pediatric patients, for whom the burden of obtaining a histological confirmation is understandably greater. Most guidelines now permit children to be diagnosed with celiac disease in the absence of a biopsy under specific circumstances (eg, characteristic symptoms of celiac disease and tTG-IgA levels > 10 times the upper limit of normal). The ACG guidelines state that “this approach is a reasonable alternative to the standard approach to a [celiac disease] diagnosis in selected children.”

The ACG does not recommend a no-biopsy approach in adults, noting that, in comparison with children, there is a relative lack of data indicating that serology is predictive in this population. However, it does recognize that physicians may encounter patients for whom a biopsy diagnosis may not be safe or practical. In such cases, an “after-the-fact” diagnosis of likely celiac disease can be given to symptomatic adult patients with a ≥ 10-fold elevation of tTG-IgA and a positive endomysial antibody in a second blood sample.

A 2024 meta-analysis of 18 studies involving over 12,103 adult patients from 15 countries concluded that a no-biopsy approach using tTG-IgA antibody levels ≥ 10 times the upper limit of normal was highly specific and predictive of celiac disease.
 

3. Celiac Disease Is Associated With Several Life-Threatening Conditions

Emerging data indicate that gastroenterologists should be vigilant in screening patients with celiac disease for several other GI conditions.

Inflammatory bowel disease and celiac disease have a strong bidirectional association, suggesting a possible genetic link between the conditions and indicating that physicians should consider the alternate diagnosis when symptoms persist after treatment.

Given the hypervigilance around food and diet inherent to celiac disease, patients are at an increased risk of developing avoidant/restrictive food intake disorder, according to a 2022 retrospective study.

In 2023, Italian investigators showed that children with celiac disease have an elevated prevalence of functional GI disorders even after adopting a GFD for a year, regardless of whether they consumed processed or natural foods. It was unclear whether this was due to a chronic inflammatory process or to nutritional factors.

Complications resulting from celiac disease are not limited to GI disorders. For a variety of underlying pathophysiological reasons, including intestinal permeability, hyposplenism, and malabsorption of nutrients, patients with celiac disease may be at a higher risk for non-GI conditions, such as osteopenia, women’s health disorders (eg, ovarian failure, endometriosis, or pregnancy loss), juvenile idiopathic arthritis in children and rheumatoid arthritis in adults, certain forms of cancer, infectious diseases, and cardiomyopathy.
 

4. GFD Is the Only Treatment, but It’s Imperfect and Frustrating for Patients

GFD is the only treatment for celiac disease and must be adhered to without deviation throughout a patient’s life.

Maintaining unwavering adherence reaps considerable benefits: Improved clinical symptoms, robust mucosal healing, and normalization of serological markers. Yet it also takes a considerable toll on patients. Patients with celiac disease struggle with a host of negative physical, psychological, and social impacts. They also report a higher treatment burden than those with gastroesophageal reflux disease or hypertension, and comparable with end-stage renal disease.

GFD also poses financial challenges. Although the price of gluten-free products has decreased in recent years, they still cost significantly more than items with gluten.

Adherence to GFD does not always equate to complete mucosal recovery. While mucosal recovery is achieved in 95% of children within 2 years of the diet’s adoption, only 34% and 66% of adults obtain it within 2 and 5 years, respectively.

GFD may lead to nutrient imbalances because gluten-free foods are typically low in alimentary fiber, micronutrients (eg, vitamin D, vitamin B12, or folate), and minerals (eg, iron, zinc, magnesium, or calcium). With higher sugar and fat content, GFD may leave patients susceptible to unwanted weight gain.

The pervasiveness of gluten in the food production system makes the risk for cross-contamination high. Gluten is often found in both naturally gluten-free foods and products labeled as such. Gluten-sensing technologies, some of which can be used via smartphone apps, have been developed to help patients identify possible cross-contamination. However, the ACG guidelines recommend against the use of these technologies until there is sufficient evidence supporting their ability to improve adherence and clinical outcomes.
 

5. Novel Therapies for Celiac Disease Are in the Pipeline

The limitations of GFD as the standard treatment for celiac disease have led to an increased focus on developing novel therapeutic interventions. They can be sorted into five key categories: Modulation of the immunostimulatory effects of toxic gluten peptides, elimination of toxic gluten peptides before they reach the intestine, induction of gluten tolerance, modulation of intestinal permeability, and restoration of gut microbiota balance.

Three therapies designed to block antigen presentation by HLA-DQ2/8, the gene alleles that predispose people to celiac disease, show promise: TPM502, an agent that contains three gluten-specific antigenic peptides with overlapping T-cell epitopes for the HLA-DQ2.5 gene; KAN-101, designed to induce gluten tolerance by targeting receptors on the liver; and DONQ52, a multi-specific antibody that targets HLA-DQ2. The KAN-101 therapy received Fast Track designation by the US Food and Drug Administration in 2022.

These and several other agents in clinical and preclinical development are discussed in detail in a 2024 review article. Although no therapies have reached phase 3 testing, when they do, it will undoubtedly be welcomed by those with celiac disease.

A version of this article first appeared on Medscape.com.

Celiac disease is a chronic, immune-mediated, systemic disorder caused by intolerance to gluten — a protein present in rye, barley, and wheat grains — that affects genetically predisposed individuals.

Due to its wide spectrum of clinical manifestations, celiac disease resembles a multisystemic disorder. Its most common gastrointestinal (GI) symptoms include chronic diarrhea, weight loss, and abdominal distention. However, celiac disease can also manifest in myriad extraintestinal symptoms, ranging from headache and fatigue to delayed puberty and psychiatric disorders, with differing presentations in children and adults.

To date, the only treatment is adopting a gluten-free diet (GFD). Although key to preventing persistent villous atrophy, the main cause of complications in celiac disease, lifelong adherence to GFD is challenging and may not resolve all clinical issues. These shortcomings have driven recent efforts to develop novel therapeutic options for patients with this disease.

Here are five things to know about celiac disease.
 

1. Rising Prevalence of Celiac Disease and Other Autoimmune Disorders Suggests Environmental Factors May Be at Play

Gluten was first identified as the cause of celiac disease in the 1950s. At that time, the condition was thought to be a relatively rare GI disease of childhood that primarily affected people of European descent, but it is now known to be a common disease affecting those of various ages, races, and ethnicities.

A 2018 meta-analysis found the pooled global prevalence of celiac disease was 1.4%. Incidence has increased by as much as 7.5% annually over the past several decades.

Increased awareness among clinicians and improved detection likely play a role in the trend. However, the growth in celiac disease is consistent with that seen for other autoimmune disorders, according to a 2024 update of evidence surrounding celiac disease. Shared environmental factors have been proposed as triggers for celiac disease and other autoimmune diseases and appear to be influencing their rise, the authors noted. These factors include migration and population growth, changing dietary patterns and food processing practices, and altered wheat consumption.
 

2. No-Biopsy Diagnosis Is Accepted for Children and Shows Promise for Adults

It is estimated that almost 60 million people worldwide have celiac disease, but most remain undiagnosed or misdiagnosed, or they experience significant diagnostic delays.

Prospective data indicate that children with first-degree relatives with celiac disease are at a significantly higher risk of developing the condition, which should prompt screening efforts in this population.

The 2023 updated guidelines from the American College of Gastroenterology (ACG) state that serology testing plays a central role in screening. This commonly involves serological testing for positive serological markers of the disease, including immunoglobulin A (IgA), anti-tissue transglutaminase IgA (tTG-IgA), anti-deamidated gliadin peptide, or endomysial antibodies.

To confirm diagnosis, clinicians have relied on intestinal biopsy since the late 1950s. The ACG still recommends esophagogastroduodenoscopy with multiple duodenal biopsies for confirmation of diagnosis in both children and adults with suspicion of celiac disease. However, recent years have seen a shift toward a no-biopsy approach.

For more than a decade in Europe, a no-biopsy approach has been established practice in pediatric patients, for whom the burden of obtaining a histological confirmation is understandably greater. Most guidelines now permit children to be diagnosed with celiac disease in the absence of a biopsy under specific circumstances (eg, characteristic symptoms of celiac disease and tTG-IgA levels > 10 times the upper limit of normal). The ACG guidelines state that “this approach is a reasonable alternative to the standard approach to a [celiac disease] diagnosis in selected children.”

The ACG does not recommend a no-biopsy approach in adults, noting that, in comparison with children, there is a relative lack of data indicating that serology is predictive in this population. However, it does recognize that physicians may encounter patients for whom a biopsy diagnosis may not be safe or practical. In such cases, an “after-the-fact” diagnosis of likely celiac disease can be given to symptomatic adult patients with a ≥ 10-fold elevation of tTG-IgA and a positive endomysial antibody in a second blood sample.

A 2024 meta-analysis of 18 studies involving over 12,103 adult patients from 15 countries concluded that a no-biopsy approach using tTG-IgA antibody levels ≥ 10 times the upper limit of normal was highly specific and predictive of celiac disease.
 

3. Celiac Disease Is Associated With Several Life-Threatening Conditions

Emerging data indicate that gastroenterologists should be vigilant in screening patients with celiac disease for several other GI conditions.

Inflammatory bowel disease and celiac disease have a strong bidirectional association, suggesting a possible genetic link between the conditions and indicating that physicians should consider the alternate diagnosis when symptoms persist after treatment.

Given the hypervigilance around food and diet inherent to celiac disease, patients are at an increased risk of developing avoidant/restrictive food intake disorder, according to a 2022 retrospective study.

In 2023, Italian investigators showed that children with celiac disease have an elevated prevalence of functional GI disorders even after adopting a GFD for a year, regardless of whether they consumed processed or natural foods. It was unclear whether this was due to a chronic inflammatory process or to nutritional factors.

Complications resulting from celiac disease are not limited to GI disorders. For a variety of underlying pathophysiological reasons, including intestinal permeability, hyposplenism, and malabsorption of nutrients, patients with celiac disease may be at a higher risk for non-GI conditions, such as osteopenia, women’s health disorders (eg, ovarian failure, endometriosis, or pregnancy loss), juvenile idiopathic arthritis in children and rheumatoid arthritis in adults, certain forms of cancer, infectious diseases, and cardiomyopathy.
 

4. GFD Is the Only Treatment, but It’s Imperfect and Frustrating for Patients

GFD is the only treatment for celiac disease and must be adhered to without deviation throughout a patient’s life.

Maintaining unwavering adherence reaps considerable benefits: Improved clinical symptoms, robust mucosal healing, and normalization of serological markers. Yet it also takes a considerable toll on patients. Patients with celiac disease struggle with a host of negative physical, psychological, and social impacts. They also report a higher treatment burden than those with gastroesophageal reflux disease or hypertension, and comparable with end-stage renal disease.

GFD also poses financial challenges. Although the price of gluten-free products has decreased in recent years, they still cost significantly more than items with gluten.

Adherence to GFD does not always equate to complete mucosal recovery. While mucosal recovery is achieved in 95% of children within 2 years of the diet’s adoption, only 34% and 66% of adults obtain it within 2 and 5 years, respectively.

GFD may lead to nutrient imbalances because gluten-free foods are typically low in alimentary fiber, micronutrients (eg, vitamin D, vitamin B12, or folate), and minerals (eg, iron, zinc, magnesium, or calcium). With higher sugar and fat content, GFD may leave patients susceptible to unwanted weight gain.

The pervasiveness of gluten in the food production system makes the risk for cross-contamination high. Gluten is often found in both naturally gluten-free foods and products labeled as such. Gluten-sensing technologies, some of which can be used via smartphone apps, have been developed to help patients identify possible cross-contamination. However, the ACG guidelines recommend against the use of these technologies until there is sufficient evidence supporting their ability to improve adherence and clinical outcomes.
 

5. Novel Therapies for Celiac Disease Are in the Pipeline

The limitations of GFD as the standard treatment for celiac disease have led to an increased focus on developing novel therapeutic interventions. They can be sorted into five key categories: Modulation of the immunostimulatory effects of toxic gluten peptides, elimination of toxic gluten peptides before they reach the intestine, induction of gluten tolerance, modulation of intestinal permeability, and restoration of gut microbiota balance.

Three therapies designed to block antigen presentation by HLA-DQ2/8, the gene alleles that predispose people to celiac disease, show promise: TPM502, an agent that contains three gluten-specific antigenic peptides with overlapping T-cell epitopes for the HLA-DQ2.5 gene; KAN-101, designed to induce gluten tolerance by targeting receptors on the liver; and DONQ52, a multi-specific antibody that targets HLA-DQ2. The KAN-101 therapy received Fast Track designation by the US Food and Drug Administration in 2022.

These and several other agents in clinical and preclinical development are discussed in detail in a 2024 review article. Although no therapies have reached phase 3 testing, when they do, it will undoubtedly be welcomed by those with celiac disease.

A version of this article first appeared on Medscape.com.

Celiac disease is a chronic, immune-mediated, systemic disorder caused by intolerance to gluten — a protein present in rye, barley, and wheat grains — that affects genetically predisposed individuals.

Due to its wide spectrum of clinical manifestations, celiac disease resembles a multisystemic disorder. Its most common gastrointestinal (GI) symptoms include chronic diarrhea, weight loss, and abdominal distention. However, celiac disease can also manifest in myriad extraintestinal symptoms, ranging from headache and fatigue to delayed puberty and psychiatric disorders, with differing presentations in children and adults.

To date, the only treatment is adopting a gluten-free diet (GFD). Although key to preventing persistent villous atrophy, the main cause of complications in celiac disease, lifelong adherence to GFD is challenging and may not resolve all clinical issues. These shortcomings have driven recent efforts to develop novel therapeutic options for patients with this disease.

Here are five things to know about celiac disease.
 

1. Rising Prevalence of Celiac Disease and Other Autoimmune Disorders Suggests Environmental Factors May Be at Play

Gluten was first identified as the cause of celiac disease in the 1950s. At that time, the condition was thought to be a relatively rare GI disease of childhood that primarily affected people of European descent, but it is now known to be a common disease affecting those of various ages, races, and ethnicities.

A 2018 meta-analysis found the pooled global prevalence of celiac disease was 1.4%. Incidence has increased by as much as 7.5% annually over the past several decades.

Increased awareness among clinicians and improved detection likely play a role in the trend. However, the growth in celiac disease is consistent with that seen for other autoimmune disorders, according to a 2024 update of evidence surrounding celiac disease. Shared environmental factors have been proposed as triggers for celiac disease and other autoimmune diseases and appear to be influencing their rise, the authors noted. These factors include migration and population growth, changing dietary patterns and food processing practices, and altered wheat consumption.
 

2. No-Biopsy Diagnosis Is Accepted for Children and Shows Promise for Adults

It is estimated that almost 60 million people worldwide have celiac disease, but most remain undiagnosed or misdiagnosed, or they experience significant diagnostic delays.

Prospective data indicate that children with first-degree relatives with celiac disease are at a significantly higher risk of developing the condition, which should prompt screening efforts in this population.

The 2023 updated guidelines from the American College of Gastroenterology (ACG) state that serology testing plays a central role in screening. This commonly involves serological testing for positive serological markers of the disease, including immunoglobulin A (IgA), anti-tissue transglutaminase IgA (tTG-IgA), anti-deamidated gliadin peptide, or endomysial antibodies.

To confirm diagnosis, clinicians have relied on intestinal biopsy since the late 1950s. The ACG still recommends esophagogastroduodenoscopy with multiple duodenal biopsies for confirmation of diagnosis in both children and adults with suspicion of celiac disease. However, recent years have seen a shift toward a no-biopsy approach.

For more than a decade in Europe, a no-biopsy approach has been established practice in pediatric patients, for whom the burden of obtaining a histological confirmation is understandably greater. Most guidelines now permit children to be diagnosed with celiac disease in the absence of a biopsy under specific circumstances (eg, characteristic symptoms of celiac disease and tTG-IgA levels > 10 times the upper limit of normal). The ACG guidelines state that “this approach is a reasonable alternative to the standard approach to a [celiac disease] diagnosis in selected children.”

The ACG does not recommend a no-biopsy approach in adults, noting that, in comparison with children, there is a relative lack of data indicating that serology is predictive in this population. However, it does recognize that physicians may encounter patients for whom a biopsy diagnosis may not be safe or practical. In such cases, an “after-the-fact” diagnosis of likely celiac disease can be given to symptomatic adult patients with a ≥ 10-fold elevation of tTG-IgA and a positive endomysial antibody in a second blood sample.

A 2024 meta-analysis of 18 studies involving over 12,103 adult patients from 15 countries concluded that a no-biopsy approach using tTG-IgA antibody levels ≥ 10 times the upper limit of normal was highly specific and predictive of celiac disease.
 

3. Celiac Disease Is Associated With Several Life-Threatening Conditions

Emerging data indicate that gastroenterologists should be vigilant in screening patients with celiac disease for several other GI conditions.

Inflammatory bowel disease and celiac disease have a strong bidirectional association, suggesting a possible genetic link between the conditions and indicating that physicians should consider the alternate diagnosis when symptoms persist after treatment.

Given the hypervigilance around food and diet inherent to celiac disease, patients are at an increased risk of developing avoidant/restrictive food intake disorder, according to a 2022 retrospective study.

In 2023, Italian investigators showed that children with celiac disease have an elevated prevalence of functional GI disorders even after adopting a GFD for a year, regardless of whether they consumed processed or natural foods. It was unclear whether this was due to a chronic inflammatory process or to nutritional factors.

Complications resulting from celiac disease are not limited to GI disorders. For a variety of underlying pathophysiological reasons, including intestinal permeability, hyposplenism, and malabsorption of nutrients, patients with celiac disease may be at a higher risk for non-GI conditions, such as osteopenia, women’s health disorders (eg, ovarian failure, endometriosis, or pregnancy loss), juvenile idiopathic arthritis in children and rheumatoid arthritis in adults, certain forms of cancer, infectious diseases, and cardiomyopathy.
 

4. GFD Is the Only Treatment, but It’s Imperfect and Frustrating for Patients

GFD is the only treatment for celiac disease and must be adhered to without deviation throughout a patient’s life.

Maintaining unwavering adherence reaps considerable benefits: Improved clinical symptoms, robust mucosal healing, and normalization of serological markers. Yet it also takes a considerable toll on patients. Patients with celiac disease struggle with a host of negative physical, psychological, and social impacts. They also report a higher treatment burden than those with gastroesophageal reflux disease or hypertension, and comparable with end-stage renal disease.

GFD also poses financial challenges. Although the price of gluten-free products has decreased in recent years, they still cost significantly more than items with gluten.

Adherence to GFD does not always equate to complete mucosal recovery. While mucosal recovery is achieved in 95% of children within 2 years of the diet’s adoption, only 34% and 66% of adults obtain it within 2 and 5 years, respectively.

GFD may lead to nutrient imbalances because gluten-free foods are typically low in alimentary fiber, micronutrients (eg, vitamin D, vitamin B12, or folate), and minerals (eg, iron, zinc, magnesium, or calcium). With higher sugar and fat content, GFD may leave patients susceptible to unwanted weight gain.

The pervasiveness of gluten in the food production system makes the risk for cross-contamination high. Gluten is often found in both naturally gluten-free foods and products labeled as such. Gluten-sensing technologies, some of which can be used via smartphone apps, have been developed to help patients identify possible cross-contamination. However, the ACG guidelines recommend against the use of these technologies until there is sufficient evidence supporting their ability to improve adherence and clinical outcomes.
 

5. Novel Therapies for Celiac Disease Are in the Pipeline

The limitations of GFD as the standard treatment for celiac disease have led to an increased focus on developing novel therapeutic interventions. They can be sorted into five key categories: Modulation of the immunostimulatory effects of toxic gluten peptides, elimination of toxic gluten peptides before they reach the intestine, induction of gluten tolerance, modulation of intestinal permeability, and restoration of gut microbiota balance.

Three therapies designed to block antigen presentation by HLA-DQ2/8, the gene alleles that predispose people to celiac disease, show promise: TPM502, an agent that contains three gluten-specific antigenic peptides with overlapping T-cell epitopes for the HLA-DQ2.5 gene; KAN-101, designed to induce gluten tolerance by targeting receptors on the liver; and DONQ52, a multi-specific antibody that targets HLA-DQ2. The KAN-101 therapy received Fast Track designation by the US Food and Drug Administration in 2022.

These and several other agents in clinical and preclinical development are discussed in detail in a 2024 review article. Although no therapies have reached phase 3 testing, when they do, it will undoubtedly be welcomed by those with celiac disease.

A version of this article first appeared on Medscape.com.

The principle of resilience and survival is crucial for medically significant fungi. These microorganisms are far from creating the postapocalyptic scenario depicted in TV series like The Last of Us, and much work is necessary to learn more about them. Accurate statistics on fungal infections, accompanied by clinical histories, simple laboratory tests, new antifungals, and a necessary One Health approach are lacking. 

The entomopathogenic fungus Ophiocordyceps unilateralis was made notorious by the TV series, but for now, it only manages to control the brains of some ants at will. Luckily, there are no signs that fungi affecting humans are inclined to create zombies.

What is clear is that the world belongs to the kingdom of fungi and that fungi are everywhere. There are already close to 150,000 described species, but millions remain to be discovered. They abound in decomposing organic matter, soil, or animal excrement, including that of bats and pigeons. Some fungi have even managed to find a home in hospitals. Lastly, we must not forget those that establish themselves in the human microbiome.

Given such diversity, it is legitimate to ask whether any of them could be capable of generating new pandemics. Could the forgotten Cryptococcus neoformans, Aspergillus fumigatus, or Histoplasma species, among others, trigger new health emergencies on the scale of the one generated by SARS-CoV-2?

We cannot forget that a coronavirus has already confirmed that reality can surpass fiction. However, Edith Sánchez Paredes, a biologist, doctor in biomedical sciences, and specialist in medical mycology, provided a reassuring response to Medscape Spanish Edition on this point.

“That would be very difficult to see because the way fungal infections are acquired is not from person to person, in most cases,” said Dr. Sánchez Paredes, from the Mycology Unit of the Faculty of Medicine at the National Autonomous University of Mexico.

Close to 300 species have already been classified as pathogenic in humans. Although the numbers are not precise and are increasing, it is estimated that around 1,500,000 people worldwide die each year of systemic fungal infections.

“However, it is important to emphasize that establishment of an infection depends not only on the causal agent. A crucial factor is the host, in this case, the human. Generally, these types of infections will develop in individuals with some deficiency in their immune system. The more deficient the immune response, the more likely a fungal infection may occur,” stated Dr. Sánchez Paredes.

The possibility of a pandemic like the one experienced with SARS-CoV-2 in the short term is remote, but the threat posed by fungal infections persists.

In 2022, the World Health Organization (WHO) defined a priority list of pathogenic fungi, with the aim of guiding actions to control them. It is mentioned there that invasive fungal diseases are on the rise worldwide, particularly in immunocompromised populations.

“Despite the growing concern, fungal infections receive very little attention and resources, leading to a paucity of quality data on fungal disease distribution and antifungal resistance patterns. Consequently, it is impossible to estimate their exact burden,” as stated in the document.

In line with this, an article published in Mycoses in 2022 concluded that fungal infections are neglected diseases in Latin America. Among other difficulties, deficiencies in access to tests such as polymerase chain reaction or serum detection of beta-1,3-D-glucan have been reported there.

In terms of treatments, most countries encounter problems with access to liposomal amphotericin B and new azoles, such as posaconazole and isavuconazole.

“Unfortunately, in Latin America, we suffer from a poor infrastructure for diagnosing fungal infections; likewise, we have limited access to antifungals available in the global market. What’s more, we lack reliable data on the epidemiology of fungal infections in the region, so many times governments are unaware of the true extent of the problem,” said Rogelio de Jesús Treviño Rangel, PhD, a medical microbiologist and expert in clinical mycology, professor, and researcher at the Faculty of Medicine of the Autonomous University of Nuevo León in Mexico.
 

Need for More Medical Mycology Training

Dr. Fernando Messina is a medical mycologist with the Mycology Unit of the Francisco Javier Muñiz Infectious Diseases Hospital in Buenos Aires, Argentina. He has noted an increase in the number of cases of cryptococcosis, histoplasmosis, and aspergillosis in his daily practice.

“Particularly, pulmonary aspergillosis is steadily increasing. This is because many patients have structural lung alterations that favor the appearance of this mycosis. This is related to the increase in cases of tuberculosis and the rise in life expectancy of patients with chronic obstructive pulmonary disease or other pulmonary or systemic diseases,” Dr. Messina stated.

For Dr. Messina, the main obstacle in current clinical practice is the low level of awareness among nonspecialist physicians regarding the presence of systemic fungal infections, and because these infections are more common than realized, it is vital to consider fungal etiology before starting empirical antibiotic therapy.

“Health professionals usually do not think about mycoses because mycology occupies a very small space in medical education at universities. As the Venezuelan mycologist Gioconda Cunto de San Blas once said, ‘Mycology is the Cinderella of microbiology.’ To change this, we need to give more space to mycoses in undergraduate and postgraduate studies,” Dr. Messina asserted.

He added, “The main challenge is to train professionals with an emphasis on the clinical interpretation of cases. Current medicine has a strong trend toward molecular biology and the use of rapid diagnostic methods, without considering the clinical symptoms or the patient’s history. Determinations are very useful, but it is necessary to interpret the results.”

Dr. Messina sees it as unlikely in the short term for a pandemic to be caused by fungi, but if it were to occur, he believes it would happen in healthcare systems in regions that are not prepared in terms of infrastructure. However, as seen in the health emergency resulting from SARS-CoV-2, he thinks the impact would be mitigated by the performance of healthcare professionals.

“In general, we have the ability to adapt to any adverse situation or change — although it is clear that we need more doctors, biochemists, and microbiologists trained in mycology,” emphasized Dr. Messina.

More than 40 interns pass through Muñiz Hospital each year. They are doctors and biochemists from Argentina, other countries in the region, or even Europe, seeking to enhance their training in mycology. Regarding fungal infection laboratory work, the interest lies in learning to use traditional techniques and innovative molecular methods.

“Rapid diagnostic methods, especially the detection of circulating antigens, have marked a change in the prognosis of deep mycosis in immunocompromised hosts. The possibility of screening and monitoring in this group of patients is very important and has a great benefit,” said Gabriela Santiso, PhD, a biochemist and head of the Mycology Unit of the Francisco Javier Muñiz Infectious Diseases Hospital.

According to Dr. Santiso, the current landscape includes the ability to identify genus and species, which can help in understanding resistance to antifungals. Furthermore, conducting sensitivity tests to these drugs, using standardized commercial methods, also provides timely information for treatment.

But Dr. Santiso warns that Latin America is a vast region with great disparity in human and technological resources. Although most countries in the region have networks facilitating access to timely diagnosis, resources are generally more available in major urban centers.

This often clashes with the epidemiology of most fungal infections. “Let’s not forget that many fungal pathologies affect low-income people who have difficulties accessing health centers, which sometimes turns them into chronic diseases that are hard to treat,” Dr. Santiso pointed out.

In mycology laboratories, the biggest cost is incurred by new diagnostic tests, such as those allowing molecular identification. Conventional methods are not usually expensive, but they require time and effort to train human resources to handle them.

Because new methodologies are not always available or easily accessible throughout the region, Dr. Santiso recommended not neglecting traditional mycological techniques. “Molecular methods, rapid diagnostic methods, and conventional mycology techniques are complementary and not mutually exclusive tests. Continuous training and updating are needed in this area,” she emphasized.
 

Why Are Resistant Fungal Infections Becoming Increasingly Common?

The first barrier for fungi to cause infection in humans is body temperature; most of them cannot withstand 37 °C. However, they also struggle to evade the immune response that is activated when they try to enter the body. 

“We are normally exposed to many of these fungi, almost all the time, but if our immune system is adequate, it may not go beyond a mild infection, in most cases subclinical, which will resolve quickly,” Dr. Sánchez Paredes stated.

However, according to Dr. Sánchez Paredes, if the immune response is weak, “the fungus will have no trouble establishing itself in our organs. Some are even part of our microbiota, such as Candida albicans, which in the face of an imbalance or immunocompromise, can lead to serious infections.”

It is clear that the population at risk for immunosuppression has increased. According to the WHO, this is due to the high prevalence of such diseases as tuberculosis, cancer, and HIV infection, among others.

But the WHO also believes that the increase in fungal infections is related to greater population access to critical care units, invasive procedures, chemotherapy, or immunotherapy treatments.

Furthermore, factors related to the fungus itself and the environment play a role. “These organisms have enzymes, proteins, and other molecules that allow them to survive in the environment in which they normally inhabit. When they face a new and stressful one, they must express other molecules that will allow them to survive. All of this helps them evade elements of the immune system, antifungals, and, of course, body temperature,” according to Dr. Sánchez Paredes.

It is possible that climate change is also behind the noticeable increase in fungal infections and that this crisis may have an even greater impact in the future. The temperature of the environment has increased, and fungi will have to adapt to the planet’s temperature, to the point where body temperature may no longer be a significant barrier for them.

Environmental changes would also be responsible for modifications in the distribution of endemic mycoses, and it is believed that fungi will more frequently find new ecological niches, be able to survive in other environments, and alter distribution zones.

This is what is happening between Mexico and the United States with coccidioidomycosis, or valley fever. “We will begin to see cases of some mycoses where they were not normally seen, so we will have to conduct more studies to confirm that the fungus is inhabiting these new areas or is simply appearing in new sites owing to migration and the great mobility of populations,” Dr. Sánchez Paredes said.

Finally, exposure to environmental factors would partly be responsible for the increasing resistance to first-line antifungals observed in these microorganisms. This seems to be the case with A. fumigatus when exposed to azoles used as fungicides in agriculture.
 

One Health in Fungal Infections

The increasing resistance to antifungals is a clear testament that human, animal, and environmental health are interconnected. This is why a multidisciplinary approach that adopts the perspective of One Health is necessary for its management.

“The use of fungicides in agriculture, structurally similar to the azoles used in clinics, generates resistance in Aspergillus fumigatus found in the environment. These fungi in humans can be associated with infections that do not respond to first-line treatment,” explained Carlos Arturo Álvarez, an infectious diseases physician and professor at the Faculty of Medicine at the National University of Colombia.

According to Dr. Álvarez, the approach to control them should not only focus on the search for diagnostic methods that allow early detection of antifungal resistance or research on new antifungal treatments. He believes that progress must also be made with strategies that allow for the proper use of antifungals in agriculture.

“Unfortunately, the One Health approach is not yet well implemented in the region, and in my view, there is a lack of articulation in the different sectors. That is, there is a need for true coordination between government offices of agriculture, animal and human health, academia, and international organizations. This is not happening yet, and I believe we are in the initial stage of visibility,” Dr. Álvarez opined.

Veterinary public health is another pillar of the aforementioned approach. For various reasons, animals experience a higher frequency of fungal infections. A few carry and transmit true zoonoses that affect human health, but most often, animals act only as sentinels indicating a potential source of transmission.

Carolina Segundo Zaragoza, PhD, has worked in veterinary mycology for 30 years. She currently heads the veterinary mycology laboratory at the Animal Production Teaching, Research, and Extension Center in Altiplano, under the Faculty of Veterinary Medicine and Animal Husbandry at the National Autonomous University of Mexico. Because she has frequent contact with specialists in human mycology, during her professional career she has received several patient consultations, most of which were for cutaneous mycoses.

“They detect some dermatomycosis and realize that the common factor is owning a companion animal or a production animal with which the patient has contact. Both animals and humans present the same type of lesions, and then comes the question: Who infected whom? I remind them that the main source of infection is the soil and that animals should not be blamed in the first instance,” Dr. Segundo Zaragoza clarified.

She is currently collaborating on a research project analyzing the presence of Coccidioides immitis in the soil. This pathogen is responsible for coccidioidomycosis in dogs and humans, and she sees with satisfaction how these types of initiatives, which include some components of the One Health vision, are becoming more common in Mexico.

“Fortunately, human mycologists are increasingly providing more space for the dissemination of veterinary mycology. So I have had the opportunity to be invited to different forums on medical mycology to present the clinical cases we can have in animals and talk about the research projects we carry out. I have more and more opportunities to conduct joint research with human mycologists and veterinary doctors,” she said.

Dr. Segundo Zaragoza believes that to better implement the One Health vision, standardizing the criteria for detecting, diagnosing, and treating mycoses is necessary. She considers that teamwork will be key to achieving the common goal of safeguarding the well-being and health of humans and animals.
 

Alarms Sound for Candida auris

The WHO included the yeast Candida auris in its group of pathogens with critical priority, and since 2009, it has raised alarm owing to the ease with which it grows in hospitals. In that setting, C auris is known for its high transmissibility, its ability to cause outbreaks, and the high mortality rate from disseminated infections.

“It has been a concern for the mycological community because it shows resistance to most antifungals used clinically, mainly azoles, but also for causing epidemic outbreaks,” emphasized Dr. Sánchez Paredes.

Its mode of transmission is not very clear, but it has been documented to be present on the skin and persist in hospital materials and furniture. It causes nosocomial infections in critically ill patients, such as those in intensive care, and those with cancer or who have received a transplant.

Risk factors for its development include renal insufficiency, hospital stays of more than 15 days, mechanical ventilation, central lines, use of parenteral nutrition, and presence of sepsis.

As for other mycoses, there are no precise studies reporting global incidence rates, but the trend indicates an increase in the detection of outbreaks in various countries lately — something that began to be visible during the COVID-19 pandemic.

In Mexico, Dr. Treviño Rangel and colleagues from Nuevo León reported the first case of candidemia caused by this agent. It occurred in May 2020 and involved a 58-year-old woman with a history of severe endometriosis and multiple complications in the gastrointestinal tract. The patient’s condition improved favorably thanks to antifungal therapy with caspofungin and liposomal amphotericin B.

However, 3 months after that episode, the group reported an outbreak of C. auris at the same hospital in 12 critically ill patients co-infected with SARS-CoV-2. All were on mechanical ventilation, had peripherally inserted central catheters and urinary catheters, and had a prolonged hospital stay (20-70 days). The mortality in patients with candidemia in this cohort was 83.3%.
 

Open Ending

As seen in some science fiction series, fungal infections in the region still have an open ending, and Global Action For Fungal Infections (GAFFI) has estimated that with better diagnostics and treatments, deaths caused by fungi could decrease to less than 750,000 per year worldwide.

But if everything continues as is, some aspects of what is to come may resemble the dystopia depicted in The Last of Us. No zombies, but emerging and reemerging fungi in a chaotic distribution, and resistant to all established treatments.

“The risk factors of patients and their immune status, combined with the behavior of mycoses, bring a complicated scenario. But therapeutic failure resulting from multidrug resistance to antifungals could make it catastrophic,” Dr. Sánchez Paredes summarized.

At the moment, there are only four families of drugs capable of counteracting fungal infections — and as mentioned, some are already scarce in Latin America’s hospital pharmacies.

“Historically, fungal infections have been given less importance than those caused by viruses or bacteria. Even in some developed countries, the true extent of morbidity and mortality they present is unknown. This results in less investment in the development of new antifungal molecules because knowledge is lacking about the incidence and prevalence of these diseases,” Dr. Treviño Rangel pointed out.

He added that the main limitation for the development of new drugs is economic. “Unfortunately, not many pharmaceutical companies are willing to invest in the development of new antifungals, and there are no government programs specifically promoting and supporting research into new therapeutic options against these neglected diseases,” he asserted.

Development of vaccines to prevent fungal infections faces the same barriers. Although, according to Dr. Treviño Rangel, the difficulties are compounded by the great similarity between fungal cells and human cells. This makes it possible for harmful cross-reactivity to occur. In addition, because most severe fungal infections occur in individuals with immunosuppression, a vaccine would need to trigger an adequate immune response despite this issue.

Meanwhile, fungi quietly continue to do what they do best: resist and survive. For millions of years, they have mutated and adapted to new environments. Some theories even blame them for the extinction of dinosaurs and the subsequent rise of mammals. They exist on the edge of life and death, decomposing and creating. There is consensus that at the moment, it does not seem feasible for them to generate a pandemic like the one due to SARS-CoV-2, given their transmission mechanism. But who is willing to rule out that this may not happen in the long or medium term?

Dr. Sánchez Paredes, Dr. Treviño Rangel, Dr. Messina, Dr. Santiso, Dr. Álvarez, and Dr. Segundo Zaragoza have declared no relevant financial conflicts of interest. 
 

This story was translated from Medscape Spanish Edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

The principle of resilience and survival is crucial for medically significant fungi. These microorganisms are far from creating the postapocalyptic scenario depicted in TV series like The Last of Us, and much work is necessary to learn more about them. Accurate statistics on fungal infections, accompanied by clinical histories, simple laboratory tests, new antifungals, and a necessary One Health approach are lacking. 

The entomopathogenic fungus Ophiocordyceps unilateralis was made notorious by the TV series, but for now, it only manages to control the brains of some ants at will. Luckily, there are no signs that fungi affecting humans are inclined to create zombies.

What is clear is that the world belongs to the kingdom of fungi and that fungi are everywhere. There are already close to 150,000 described species, but millions remain to be discovered. They abound in decomposing organic matter, soil, or animal excrement, including that of bats and pigeons. Some fungi have even managed to find a home in hospitals. Lastly, we must not forget those that establish themselves in the human microbiome.

Given such diversity, it is legitimate to ask whether any of them could be capable of generating new pandemics. Could the forgotten Cryptococcus neoformans, Aspergillus fumigatus, or Histoplasma species, among others, trigger new health emergencies on the scale of the one generated by SARS-CoV-2?

We cannot forget that a coronavirus has already confirmed that reality can surpass fiction. However, Edith Sánchez Paredes, a biologist, doctor in biomedical sciences, and specialist in medical mycology, provided a reassuring response to Medscape Spanish Edition on this point.

“That would be very difficult to see because the way fungal infections are acquired is not from person to person, in most cases,” said Dr. Sánchez Paredes, from the Mycology Unit of the Faculty of Medicine at the National Autonomous University of Mexico.

Close to 300 species have already been classified as pathogenic in humans. Although the numbers are not precise and are increasing, it is estimated that around 1,500,000 people worldwide die each year of systemic fungal infections.

“However, it is important to emphasize that establishment of an infection depends not only on the causal agent. A crucial factor is the host, in this case, the human. Generally, these types of infections will develop in individuals with some deficiency in their immune system. The more deficient the immune response, the more likely a fungal infection may occur,” stated Dr. Sánchez Paredes.

The possibility of a pandemic like the one experienced with SARS-CoV-2 in the short term is remote, but the threat posed by fungal infections persists.

In 2022, the World Health Organization (WHO) defined a priority list of pathogenic fungi, with the aim of guiding actions to control them. It is mentioned there that invasive fungal diseases are on the rise worldwide, particularly in immunocompromised populations.

“Despite the growing concern, fungal infections receive very little attention and resources, leading to a paucity of quality data on fungal disease distribution and antifungal resistance patterns. Consequently, it is impossible to estimate their exact burden,” as stated in the document.

In line with this, an article published in Mycoses in 2022 concluded that fungal infections are neglected diseases in Latin America. Among other difficulties, deficiencies in access to tests such as polymerase chain reaction or serum detection of beta-1,3-D-glucan have been reported there.

In terms of treatments, most countries encounter problems with access to liposomal amphotericin B and new azoles, such as posaconazole and isavuconazole.

“Unfortunately, in Latin America, we suffer from a poor infrastructure for diagnosing fungal infections; likewise, we have limited access to antifungals available in the global market. What’s more, we lack reliable data on the epidemiology of fungal infections in the region, so many times governments are unaware of the true extent of the problem,” said Rogelio de Jesús Treviño Rangel, PhD, a medical microbiologist and expert in clinical mycology, professor, and researcher at the Faculty of Medicine of the Autonomous University of Nuevo León in Mexico.
 

Need for More Medical Mycology Training

Dr. Fernando Messina is a medical mycologist with the Mycology Unit of the Francisco Javier Muñiz Infectious Diseases Hospital in Buenos Aires, Argentina. He has noted an increase in the number of cases of cryptococcosis, histoplasmosis, and aspergillosis in his daily practice.

“Particularly, pulmonary aspergillosis is steadily increasing. This is because many patients have structural lung alterations that favor the appearance of this mycosis. This is related to the increase in cases of tuberculosis and the rise in life expectancy of patients with chronic obstructive pulmonary disease or other pulmonary or systemic diseases,” Dr. Messina stated.

For Dr. Messina, the main obstacle in current clinical practice is the low level of awareness among nonspecialist physicians regarding the presence of systemic fungal infections, and because these infections are more common than realized, it is vital to consider fungal etiology before starting empirical antibiotic therapy.

“Health professionals usually do not think about mycoses because mycology occupies a very small space in medical education at universities. As the Venezuelan mycologist Gioconda Cunto de San Blas once said, ‘Mycology is the Cinderella of microbiology.’ To change this, we need to give more space to mycoses in undergraduate and postgraduate studies,” Dr. Messina asserted.

He added, “The main challenge is to train professionals with an emphasis on the clinical interpretation of cases. Current medicine has a strong trend toward molecular biology and the use of rapid diagnostic methods, without considering the clinical symptoms or the patient’s history. Determinations are very useful, but it is necessary to interpret the results.”

Dr. Messina sees it as unlikely in the short term for a pandemic to be caused by fungi, but if it were to occur, he believes it would happen in healthcare systems in regions that are not prepared in terms of infrastructure. However, as seen in the health emergency resulting from SARS-CoV-2, he thinks the impact would be mitigated by the performance of healthcare professionals.

“In general, we have the ability to adapt to any adverse situation or change — although it is clear that we need more doctors, biochemists, and microbiologists trained in mycology,” emphasized Dr. Messina.

More than 40 interns pass through Muñiz Hospital each year. They are doctors and biochemists from Argentina, other countries in the region, or even Europe, seeking to enhance their training in mycology. Regarding fungal infection laboratory work, the interest lies in learning to use traditional techniques and innovative molecular methods.

“Rapid diagnostic methods, especially the detection of circulating antigens, have marked a change in the prognosis of deep mycosis in immunocompromised hosts. The possibility of screening and monitoring in this group of patients is very important and has a great benefit,” said Gabriela Santiso, PhD, a biochemist and head of the Mycology Unit of the Francisco Javier Muñiz Infectious Diseases Hospital.

According to Dr. Santiso, the current landscape includes the ability to identify genus and species, which can help in understanding resistance to antifungals. Furthermore, conducting sensitivity tests to these drugs, using standardized commercial methods, also provides timely information for treatment.

But Dr. Santiso warns that Latin America is a vast region with great disparity in human and technological resources. Although most countries in the region have networks facilitating access to timely diagnosis, resources are generally more available in major urban centers.

This often clashes with the epidemiology of most fungal infections. “Let’s not forget that many fungal pathologies affect low-income people who have difficulties accessing health centers, which sometimes turns them into chronic diseases that are hard to treat,” Dr. Santiso pointed out.

In mycology laboratories, the biggest cost is incurred by new diagnostic tests, such as those allowing molecular identification. Conventional methods are not usually expensive, but they require time and effort to train human resources to handle them.

Because new methodologies are not always available or easily accessible throughout the region, Dr. Santiso recommended not neglecting traditional mycological techniques. “Molecular methods, rapid diagnostic methods, and conventional mycology techniques are complementary and not mutually exclusive tests. Continuous training and updating are needed in this area,” she emphasized.
 

Why Are Resistant Fungal Infections Becoming Increasingly Common?

The first barrier for fungi to cause infection in humans is body temperature; most of them cannot withstand 37 °C. However, they also struggle to evade the immune response that is activated when they try to enter the body. 

“We are normally exposed to many of these fungi, almost all the time, but if our immune system is adequate, it may not go beyond a mild infection, in most cases subclinical, which will resolve quickly,” Dr. Sánchez Paredes stated.

However, according to Dr. Sánchez Paredes, if the immune response is weak, “the fungus will have no trouble establishing itself in our organs. Some are even part of our microbiota, such as Candida albicans, which in the face of an imbalance or immunocompromise, can lead to serious infections.”

It is clear that the population at risk for immunosuppression has increased. According to the WHO, this is due to the high prevalence of such diseases as tuberculosis, cancer, and HIV infection, among others.

But the WHO also believes that the increase in fungal infections is related to greater population access to critical care units, invasive procedures, chemotherapy, or immunotherapy treatments.

Furthermore, factors related to the fungus itself and the environment play a role. “These organisms have enzymes, proteins, and other molecules that allow them to survive in the environment in which they normally inhabit. When they face a new and stressful one, they must express other molecules that will allow them to survive. All of this helps them evade elements of the immune system, antifungals, and, of course, body temperature,” according to Dr. Sánchez Paredes.

It is possible that climate change is also behind the noticeable increase in fungal infections and that this crisis may have an even greater impact in the future. The temperature of the environment has increased, and fungi will have to adapt to the planet’s temperature, to the point where body temperature may no longer be a significant barrier for them.

Environmental changes would also be responsible for modifications in the distribution of endemic mycoses, and it is believed that fungi will more frequently find new ecological niches, be able to survive in other environments, and alter distribution zones.

This is what is happening between Mexico and the United States with coccidioidomycosis, or valley fever. “We will begin to see cases of some mycoses where they were not normally seen, so we will have to conduct more studies to confirm that the fungus is inhabiting these new areas or is simply appearing in new sites owing to migration and the great mobility of populations,” Dr. Sánchez Paredes said.

Finally, exposure to environmental factors would partly be responsible for the increasing resistance to first-line antifungals observed in these microorganisms. This seems to be the case with A. fumigatus when exposed to azoles used as fungicides in agriculture.
 

One Health in Fungal Infections

The increasing resistance to antifungals is a clear testament that human, animal, and environmental health are interconnected. This is why a multidisciplinary approach that adopts the perspective of One Health is necessary for its management.

“The use of fungicides in agriculture, structurally similar to the azoles used in clinics, generates resistance in Aspergillus fumigatus found in the environment. These fungi in humans can be associated with infections that do not respond to first-line treatment,” explained Carlos Arturo Álvarez, an infectious diseases physician and professor at the Faculty of Medicine at the National University of Colombia.

According to Dr. Álvarez, the approach to control them should not only focus on the search for diagnostic methods that allow early detection of antifungal resistance or research on new antifungal treatments. He believes that progress must also be made with strategies that allow for the proper use of antifungals in agriculture.

“Unfortunately, the One Health approach is not yet well implemented in the region, and in my view, there is a lack of articulation in the different sectors. That is, there is a need for true coordination between government offices of agriculture, animal and human health, academia, and international organizations. This is not happening yet, and I believe we are in the initial stage of visibility,” Dr. Álvarez opined.

Veterinary public health is another pillar of the aforementioned approach. For various reasons, animals experience a higher frequency of fungal infections. A few carry and transmit true zoonoses that affect human health, but most often, animals act only as sentinels indicating a potential source of transmission.

Carolina Segundo Zaragoza, PhD, has worked in veterinary mycology for 30 years. She currently heads the veterinary mycology laboratory at the Animal Production Teaching, Research, and Extension Center in Altiplano, under the Faculty of Veterinary Medicine and Animal Husbandry at the National Autonomous University of Mexico. Because she has frequent contact with specialists in human mycology, during her professional career she has received several patient consultations, most of which were for cutaneous mycoses.

“They detect some dermatomycosis and realize that the common factor is owning a companion animal or a production animal with which the patient has contact. Both animals and humans present the same type of lesions, and then comes the question: Who infected whom? I remind them that the main source of infection is the soil and that animals should not be blamed in the first instance,” Dr. Segundo Zaragoza clarified.

She is currently collaborating on a research project analyzing the presence of Coccidioides immitis in the soil. This pathogen is responsible for coccidioidomycosis in dogs and humans, and she sees with satisfaction how these types of initiatives, which include some components of the One Health vision, are becoming more common in Mexico.

“Fortunately, human mycologists are increasingly providing more space for the dissemination of veterinary mycology. So I have had the opportunity to be invited to different forums on medical mycology to present the clinical cases we can have in animals and talk about the research projects we carry out. I have more and more opportunities to conduct joint research with human mycologists and veterinary doctors,” she said.

Dr. Segundo Zaragoza believes that to better implement the One Health vision, standardizing the criteria for detecting, diagnosing, and treating mycoses is necessary. She considers that teamwork will be key to achieving the common goal of safeguarding the well-being and health of humans and animals.
 

Alarms Sound for Candida auris

The WHO included the yeast Candida auris in its group of pathogens with critical priority, and since 2009, it has raised alarm owing to the ease with which it grows in hospitals. In that setting, C auris is known for its high transmissibility, its ability to cause outbreaks, and the high mortality rate from disseminated infections.

“It has been a concern for the mycological community because it shows resistance to most antifungals used clinically, mainly azoles, but also for causing epidemic outbreaks,” emphasized Dr. Sánchez Paredes.

Its mode of transmission is not very clear, but it has been documented to be present on the skin and persist in hospital materials and furniture. It causes nosocomial infections in critically ill patients, such as those in intensive care, and those with cancer or who have received a transplant.

Risk factors for its development include renal insufficiency, hospital stays of more than 15 days, mechanical ventilation, central lines, use of parenteral nutrition, and presence of sepsis.

As for other mycoses, there are no precise studies reporting global incidence rates, but the trend indicates an increase in the detection of outbreaks in various countries lately — something that began to be visible during the COVID-19 pandemic.

In Mexico, Dr. Treviño Rangel and colleagues from Nuevo León reported the first case of candidemia caused by this agent. It occurred in May 2020 and involved a 58-year-old woman with a history of severe endometriosis and multiple complications in the gastrointestinal tract. The patient’s condition improved favorably thanks to antifungal therapy with caspofungin and liposomal amphotericin B.

However, 3 months after that episode, the group reported an outbreak of C. auris at the same hospital in 12 critically ill patients co-infected with SARS-CoV-2. All were on mechanical ventilation, had peripherally inserted central catheters and urinary catheters, and had a prolonged hospital stay (20-70 days). The mortality in patients with candidemia in this cohort was 83.3%.
 

Open Ending

As seen in some science fiction series, fungal infections in the region still have an open ending, and Global Action For Fungal Infections (GAFFI) has estimated that with better diagnostics and treatments, deaths caused by fungi could decrease to less than 750,000 per year worldwide.

But if everything continues as is, some aspects of what is to come may resemble the dystopia depicted in The Last of Us. No zombies, but emerging and reemerging fungi in a chaotic distribution, and resistant to all established treatments.

“The risk factors of patients and their immune status, combined with the behavior of mycoses, bring a complicated scenario. But therapeutic failure resulting from multidrug resistance to antifungals could make it catastrophic,” Dr. Sánchez Paredes summarized.

At the moment, there are only four families of drugs capable of counteracting fungal infections — and as mentioned, some are already scarce in Latin America’s hospital pharmacies.

“Historically, fungal infections have been given less importance than those caused by viruses or bacteria. Even in some developed countries, the true extent of morbidity and mortality they present is unknown. This results in less investment in the development of new antifungal molecules because knowledge is lacking about the incidence and prevalence of these diseases,” Dr. Treviño Rangel pointed out.

He added that the main limitation for the development of new drugs is economic. “Unfortunately, not many pharmaceutical companies are willing to invest in the development of new antifungals, and there are no government programs specifically promoting and supporting research into new therapeutic options against these neglected diseases,” he asserted.

Development of vaccines to prevent fungal infections faces the same barriers. Although, according to Dr. Treviño Rangel, the difficulties are compounded by the great similarity between fungal cells and human cells. This makes it possible for harmful cross-reactivity to occur. In addition, because most severe fungal infections occur in individuals with immunosuppression, a vaccine would need to trigger an adequate immune response despite this issue.

Meanwhile, fungi quietly continue to do what they do best: resist and survive. For millions of years, they have mutated and adapted to new environments. Some theories even blame them for the extinction of dinosaurs and the subsequent rise of mammals. They exist on the edge of life and death, decomposing and creating. There is consensus that at the moment, it does not seem feasible for them to generate a pandemic like the one due to SARS-CoV-2, given their transmission mechanism. But who is willing to rule out that this may not happen in the long or medium term?

Dr. Sánchez Paredes, Dr. Treviño Rangel, Dr. Messina, Dr. Santiso, Dr. Álvarez, and Dr. Segundo Zaragoza have declared no relevant financial conflicts of interest. 
 

This story was translated from Medscape Spanish Edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

The principle of resilience and survival is crucial for medically significant fungi. These microorganisms are far from creating the postapocalyptic scenario depicted in TV series like The Last of Us, and much work is necessary to learn more about them. Accurate statistics on fungal infections, accompanied by clinical histories, simple laboratory tests, new antifungals, and a necessary One Health approach are lacking. 

The entomopathogenic fungus Ophiocordyceps unilateralis was made notorious by the TV series, but for now, it only manages to control the brains of some ants at will. Luckily, there are no signs that fungi affecting humans are inclined to create zombies.

What is clear is that the world belongs to the kingdom of fungi and that fungi are everywhere. There are already close to 150,000 described species, but millions remain to be discovered. They abound in decomposing organic matter, soil, or animal excrement, including that of bats and pigeons. Some fungi have even managed to find a home in hospitals. Lastly, we must not forget those that establish themselves in the human microbiome.

Given such diversity, it is legitimate to ask whether any of them could be capable of generating new pandemics. Could the forgotten Cryptococcus neoformans, Aspergillus fumigatus, or Histoplasma species, among others, trigger new health emergencies on the scale of the one generated by SARS-CoV-2?

We cannot forget that a coronavirus has already confirmed that reality can surpass fiction. However, Edith Sánchez Paredes, a biologist, doctor in biomedical sciences, and specialist in medical mycology, provided a reassuring response to Medscape Spanish Edition on this point.

“That would be very difficult to see because the way fungal infections are acquired is not from person to person, in most cases,” said Dr. Sánchez Paredes, from the Mycology Unit of the Faculty of Medicine at the National Autonomous University of Mexico.

Close to 300 species have already been classified as pathogenic in humans. Although the numbers are not precise and are increasing, it is estimated that around 1,500,000 people worldwide die each year of systemic fungal infections.

“However, it is important to emphasize that establishment of an infection depends not only on the causal agent. A crucial factor is the host, in this case, the human. Generally, these types of infections will develop in individuals with some deficiency in their immune system. The more deficient the immune response, the more likely a fungal infection may occur,” stated Dr. Sánchez Paredes.

The possibility of a pandemic like the one experienced with SARS-CoV-2 in the short term is remote, but the threat posed by fungal infections persists.

In 2022, the World Health Organization (WHO) defined a priority list of pathogenic fungi, with the aim of guiding actions to control them. It is mentioned there that invasive fungal diseases are on the rise worldwide, particularly in immunocompromised populations.

“Despite the growing concern, fungal infections receive very little attention and resources, leading to a paucity of quality data on fungal disease distribution and antifungal resistance patterns. Consequently, it is impossible to estimate their exact burden,” as stated in the document.

In line with this, an article published in Mycoses in 2022 concluded that fungal infections are neglected diseases in Latin America. Among other difficulties, deficiencies in access to tests such as polymerase chain reaction or serum detection of beta-1,3-D-glucan have been reported there.

In terms of treatments, most countries encounter problems with access to liposomal amphotericin B and new azoles, such as posaconazole and isavuconazole.

“Unfortunately, in Latin America, we suffer from a poor infrastructure for diagnosing fungal infections; likewise, we have limited access to antifungals available in the global market. What’s more, we lack reliable data on the epidemiology of fungal infections in the region, so many times governments are unaware of the true extent of the problem,” said Rogelio de Jesús Treviño Rangel, PhD, a medical microbiologist and expert in clinical mycology, professor, and researcher at the Faculty of Medicine of the Autonomous University of Nuevo León in Mexico.
 

Need for More Medical Mycology Training

Dr. Fernando Messina is a medical mycologist with the Mycology Unit of the Francisco Javier Muñiz Infectious Diseases Hospital in Buenos Aires, Argentina. He has noted an increase in the number of cases of cryptococcosis, histoplasmosis, and aspergillosis in his daily practice.

“Particularly, pulmonary aspergillosis is steadily increasing. This is because many patients have structural lung alterations that favor the appearance of this mycosis. This is related to the increase in cases of tuberculosis and the rise in life expectancy of patients with chronic obstructive pulmonary disease or other pulmonary or systemic diseases,” Dr. Messina stated.

For Dr. Messina, the main obstacle in current clinical practice is the low level of awareness among nonspecialist physicians regarding the presence of systemic fungal infections, and because these infections are more common than realized, it is vital to consider fungal etiology before starting empirical antibiotic therapy.

“Health professionals usually do not think about mycoses because mycology occupies a very small space in medical education at universities. As the Venezuelan mycologist Gioconda Cunto de San Blas once said, ‘Mycology is the Cinderella of microbiology.’ To change this, we need to give more space to mycoses in undergraduate and postgraduate studies,” Dr. Messina asserted.

He added, “The main challenge is to train professionals with an emphasis on the clinical interpretation of cases. Current medicine has a strong trend toward molecular biology and the use of rapid diagnostic methods, without considering the clinical symptoms or the patient’s history. Determinations are very useful, but it is necessary to interpret the results.”

Dr. Messina sees it as unlikely in the short term for a pandemic to be caused by fungi, but if it were to occur, he believes it would happen in healthcare systems in regions that are not prepared in terms of infrastructure. However, as seen in the health emergency resulting from SARS-CoV-2, he thinks the impact would be mitigated by the performance of healthcare professionals.

“In general, we have the ability to adapt to any adverse situation or change — although it is clear that we need more doctors, biochemists, and microbiologists trained in mycology,” emphasized Dr. Messina.

More than 40 interns pass through Muñiz Hospital each year. They are doctors and biochemists from Argentina, other countries in the region, or even Europe, seeking to enhance their training in mycology. Regarding fungal infection laboratory work, the interest lies in learning to use traditional techniques and innovative molecular methods.

“Rapid diagnostic methods, especially the detection of circulating antigens, have marked a change in the prognosis of deep mycosis in immunocompromised hosts. The possibility of screening and monitoring in this group of patients is very important and has a great benefit,” said Gabriela Santiso, PhD, a biochemist and head of the Mycology Unit of the Francisco Javier Muñiz Infectious Diseases Hospital.

According to Dr. Santiso, the current landscape includes the ability to identify genus and species, which can help in understanding resistance to antifungals. Furthermore, conducting sensitivity tests to these drugs, using standardized commercial methods, also provides timely information for treatment.

But Dr. Santiso warns that Latin America is a vast region with great disparity in human and technological resources. Although most countries in the region have networks facilitating access to timely diagnosis, resources are generally more available in major urban centers.

This often clashes with the epidemiology of most fungal infections. “Let’s not forget that many fungal pathologies affect low-income people who have difficulties accessing health centers, which sometimes turns them into chronic diseases that are hard to treat,” Dr. Santiso pointed out.

In mycology laboratories, the biggest cost is incurred by new diagnostic tests, such as those allowing molecular identification. Conventional methods are not usually expensive, but they require time and effort to train human resources to handle them.

Because new methodologies are not always available or easily accessible throughout the region, Dr. Santiso recommended not neglecting traditional mycological techniques. “Molecular methods, rapid diagnostic methods, and conventional mycology techniques are complementary and not mutually exclusive tests. Continuous training and updating are needed in this area,” she emphasized.
 

Why Are Resistant Fungal Infections Becoming Increasingly Common?

The first barrier for fungi to cause infection in humans is body temperature; most of them cannot withstand 37 °C. However, they also struggle to evade the immune response that is activated when they try to enter the body. 

“We are normally exposed to many of these fungi, almost all the time, but if our immune system is adequate, it may not go beyond a mild infection, in most cases subclinical, which will resolve quickly,” Dr. Sánchez Paredes stated.

However, according to Dr. Sánchez Paredes, if the immune response is weak, “the fungus will have no trouble establishing itself in our organs. Some are even part of our microbiota, such as Candida albicans, which in the face of an imbalance or immunocompromise, can lead to serious infections.”

It is clear that the population at risk for immunosuppression has increased. According to the WHO, this is due to the high prevalence of such diseases as tuberculosis, cancer, and HIV infection, among others.

But the WHO also believes that the increase in fungal infections is related to greater population access to critical care units, invasive procedures, chemotherapy, or immunotherapy treatments.

Furthermore, factors related to the fungus itself and the environment play a role. “These organisms have enzymes, proteins, and other molecules that allow them to survive in the environment in which they normally inhabit. When they face a new and stressful one, they must express other molecules that will allow them to survive. All of this helps them evade elements of the immune system, antifungals, and, of course, body temperature,” according to Dr. Sánchez Paredes.

It is possible that climate change is also behind the noticeable increase in fungal infections and that this crisis may have an even greater impact in the future. The temperature of the environment has increased, and fungi will have to adapt to the planet’s temperature, to the point where body temperature may no longer be a significant barrier for them.

Environmental changes would also be responsible for modifications in the distribution of endemic mycoses, and it is believed that fungi will more frequently find new ecological niches, be able to survive in other environments, and alter distribution zones.

This is what is happening between Mexico and the United States with coccidioidomycosis, or valley fever. “We will begin to see cases of some mycoses where they were not normally seen, so we will have to conduct more studies to confirm that the fungus is inhabiting these new areas or is simply appearing in new sites owing to migration and the great mobility of populations,” Dr. Sánchez Paredes said.

Finally, exposure to environmental factors would partly be responsible for the increasing resistance to first-line antifungals observed in these microorganisms. This seems to be the case with A. fumigatus when exposed to azoles used as fungicides in agriculture.
 

One Health in Fungal Infections

The increasing resistance to antifungals is a clear testament that human, animal, and environmental health are interconnected. This is why a multidisciplinary approach that adopts the perspective of One Health is necessary for its management.

“The use of fungicides in agriculture, structurally similar to the azoles used in clinics, generates resistance in Aspergillus fumigatus found in the environment. These fungi in humans can be associated with infections that do not respond to first-line treatment,” explained Carlos Arturo Álvarez, an infectious diseases physician and professor at the Faculty of Medicine at the National University of Colombia.

According to Dr. Álvarez, the approach to control them should not only focus on the search for diagnostic methods that allow early detection of antifungal resistance or research on new antifungal treatments. He believes that progress must also be made with strategies that allow for the proper use of antifungals in agriculture.

“Unfortunately, the One Health approach is not yet well implemented in the region, and in my view, there is a lack of articulation in the different sectors. That is, there is a need for true coordination between government offices of agriculture, animal and human health, academia, and international organizations. This is not happening yet, and I believe we are in the initial stage of visibility,” Dr. Álvarez opined.

Veterinary public health is another pillar of the aforementioned approach. For various reasons, animals experience a higher frequency of fungal infections. A few carry and transmit true zoonoses that affect human health, but most often, animals act only as sentinels indicating a potential source of transmission.

Carolina Segundo Zaragoza, PhD, has worked in veterinary mycology for 30 years. She currently heads the veterinary mycology laboratory at the Animal Production Teaching, Research, and Extension Center in Altiplano, under the Faculty of Veterinary Medicine and Animal Husbandry at the National Autonomous University of Mexico. Because she has frequent contact with specialists in human mycology, during her professional career she has received several patient consultations, most of which were for cutaneous mycoses.

“They detect some dermatomycosis and realize that the common factor is owning a companion animal or a production animal with which the patient has contact. Both animals and humans present the same type of lesions, and then comes the question: Who infected whom? I remind them that the main source of infection is the soil and that animals should not be blamed in the first instance,” Dr. Segundo Zaragoza clarified.

She is currently collaborating on a research project analyzing the presence of Coccidioides immitis in the soil. This pathogen is responsible for coccidioidomycosis in dogs and humans, and she sees with satisfaction how these types of initiatives, which include some components of the One Health vision, are becoming more common in Mexico.

“Fortunately, human mycologists are increasingly providing more space for the dissemination of veterinary mycology. So I have had the opportunity to be invited to different forums on medical mycology to present the clinical cases we can have in animals and talk about the research projects we carry out. I have more and more opportunities to conduct joint research with human mycologists and veterinary doctors,” she said.

Dr. Segundo Zaragoza believes that to better implement the One Health vision, standardizing the criteria for detecting, diagnosing, and treating mycoses is necessary. She considers that teamwork will be key to achieving the common goal of safeguarding the well-being and health of humans and animals.
 

Alarms Sound for Candida auris

The WHO included the yeast Candida auris in its group of pathogens with critical priority, and since 2009, it has raised alarm owing to the ease with which it grows in hospitals. In that setting, C auris is known for its high transmissibility, its ability to cause outbreaks, and the high mortality rate from disseminated infections.

“It has been a concern for the mycological community because it shows resistance to most antifungals used clinically, mainly azoles, but also for causing epidemic outbreaks,” emphasized Dr. Sánchez Paredes.

Its mode of transmission is not very clear, but it has been documented to be present on the skin and persist in hospital materials and furniture. It causes nosocomial infections in critically ill patients, such as those in intensive care, and those with cancer or who have received a transplant.

Risk factors for its development include renal insufficiency, hospital stays of more than 15 days, mechanical ventilation, central lines, use of parenteral nutrition, and presence of sepsis.

As for other mycoses, there are no precise studies reporting global incidence rates, but the trend indicates an increase in the detection of outbreaks in various countries lately — something that began to be visible during the COVID-19 pandemic.

In Mexico, Dr. Treviño Rangel and colleagues from Nuevo León reported the first case of candidemia caused by this agent. It occurred in May 2020 and involved a 58-year-old woman with a history of severe endometriosis and multiple complications in the gastrointestinal tract. The patient’s condition improved favorably thanks to antifungal therapy with caspofungin and liposomal amphotericin B.

However, 3 months after that episode, the group reported an outbreak of C. auris at the same hospital in 12 critically ill patients co-infected with SARS-CoV-2. All were on mechanical ventilation, had peripherally inserted central catheters and urinary catheters, and had a prolonged hospital stay (20-70 days). The mortality in patients with candidemia in this cohort was 83.3%.
 

Open Ending

As seen in some science fiction series, fungal infections in the region still have an open ending, and Global Action For Fungal Infections (GAFFI) has estimated that with better diagnostics and treatments, deaths caused by fungi could decrease to less than 750,000 per year worldwide.

But if everything continues as is, some aspects of what is to come may resemble the dystopia depicted in The Last of Us. No zombies, but emerging and reemerging fungi in a chaotic distribution, and resistant to all established treatments.

“The risk factors of patients and their immune status, combined with the behavior of mycoses, bring a complicated scenario. But therapeutic failure resulting from multidrug resistance to antifungals could make it catastrophic,” Dr. Sánchez Paredes summarized.

At the moment, there are only four families of drugs capable of counteracting fungal infections — and as mentioned, some are already scarce in Latin America’s hospital pharmacies.

“Historically, fungal infections have been given less importance than those caused by viruses or bacteria. Even in some developed countries, the true extent of morbidity and mortality they present is unknown. This results in less investment in the development of new antifungal molecules because knowledge is lacking about the incidence and prevalence of these diseases,” Dr. Treviño Rangel pointed out.

He added that the main limitation for the development of new drugs is economic. “Unfortunately, not many pharmaceutical companies are willing to invest in the development of new antifungals, and there are no government programs specifically promoting and supporting research into new therapeutic options against these neglected diseases,” he asserted.

Development of vaccines to prevent fungal infections faces the same barriers. Although, according to Dr. Treviño Rangel, the difficulties are compounded by the great similarity between fungal cells and human cells. This makes it possible for harmful cross-reactivity to occur. In addition, because most severe fungal infections occur in individuals with immunosuppression, a vaccine would need to trigger an adequate immune response despite this issue.

Meanwhile, fungi quietly continue to do what they do best: resist and survive. For millions of years, they have mutated and adapted to new environments. Some theories even blame them for the extinction of dinosaurs and the subsequent rise of mammals. They exist on the edge of life and death, decomposing and creating. There is consensus that at the moment, it does not seem feasible for them to generate a pandemic like the one due to SARS-CoV-2, given their transmission mechanism. But who is willing to rule out that this may not happen in the long or medium term?

Dr. Sánchez Paredes, Dr. Treviño Rangel, Dr. Messina, Dr. Santiso, Dr. Álvarez, and Dr. Segundo Zaragoza have declared no relevant financial conflicts of interest. 
 

This story was translated from Medscape Spanish Edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication. A version of this article appeared on Medscape.com.

The Diagnosis: Spiradenocylindroma

Shave biopsies of our patient’s lesions showed wellcircumscribed dermal nodules resembling a spiradenoma with 3 cell populations: those with lighter nuclei, darker nuclei, and scattered lymphocytes. However, the conspicuous globules of basement membrane material were reminiscent of a cylindroma. These overlapping features and the patient’s history of cylindroma were suggestive of a diagnosis of spiradenocylindroma.

Spiradenocylindroma is an uncommon dermal tumor with features that overlap with spiradenoma and cylindroma.¹ It may manifest as a solitary lesion or multiple lesions and can occur sporadically or in the context of a family history. Histologically, it must be distinguished from other intradermal basaloid neoplasms including conventional cylindroma and spiradenoma, dermal duct tumor, hidradenoma, and trichoblastoma.

When patients present with multiple cylindromas, spiradenomas, or spiradenocylindromas, physicians should consider genetic testing and review of the family history to assess for cylindromatosis gene mutations or Brooke-Spiegler syndrome. Biopsy and histologic examination are important because malignant tumors can evolve from pre-existing spiradenocylindromas, cylindromas, and spiradenomas,² with an increased risk in patients with Brooke-Spiegler syndrome.¹ Our patient declined further genetic workup but continues to follow up with dermatology for monitoring of lesions.

Dermal duct tumors are morphologic variants of poromas that are derived from sweat gland lineage and usually manifest as solitary dome-shaped papules, plaques, or nodules most often seen on acral surfaces as well as the head and neck.³ Clinically, they may be indistinguishable from spiradenocylindromas and require biopsy for histologic evaluation. They can be distinguished from spiradenocylindroma by the presence of small dermal nodules composed of cuboidal cells with ample pink cytoplasm and cuticle-lined ducts (Figure 1).

Trichoblastomas typically are deep-seated basaloid follicular neoplasms on the scalp with papillary mesenchyme resembling the normal fibrous sheath of the hair follicle, often replete with papillary mesenchymal bodies (Figure 2). There generally are no retraction spaces between its basaloid nests and the surrounding stroma, which is unlikely to contain mucin relative to basal cell carcinoma (BCC).^4,5

Adenoid cystic carcinoma is a rare salivary gland tumor that can metastasize to the skin and rarely arises as a primary skin adnexal tumor. It manifests as a slowgrowing mass that can be tender to palpation.⁶ Histologic examination shows dermal islands with cribriform blue and pink spaces. Compared to BCC, adenoid cystic carcinoma cells are enlarged and epithelioid with relatively scarce cytoplasm (Figure 3).^6,7 Adenoid cystic carcinoma can show variable growth patterns including infiltrative nests and trabeculae. Perineural invasion is common, and there is a high risk for local recurrence.⁷ First-line therapy usually is surgical, and postoperative radiotherapy may be required.^6,7

Nodular BCC commonly manifests as an enlarging nonhealing lesion on sun-exposed skin and has many subtypes, typically with arborizing telangiectases on dermoscopy. Histopathologic examination of nodular BCC reveals a nest of basaloid follicular germinative cells in the dermis with peripheral palisading and a fibromyxoid stroma (Figure 4).⁸ Patients with Brooke-Spiegler syndrome are at increased risk for nodular BCC, which may be clinically indistinguishable from spiradenoma, cylindroma, and spiradenocylindroma, necessitating histologic assessment.

The Diagnosis: Spiradenocylindroma

Shave biopsies of our patient’s lesions showed wellcircumscribed dermal nodules resembling a spiradenoma with 3 cell populations: those with lighter nuclei, darker nuclei, and scattered lymphocytes. However, the conspicuous globules of basement membrane material were reminiscent of a cylindroma. These overlapping features and the patient’s history of cylindroma were suggestive of a diagnosis of spiradenocylindroma.

Spiradenocylindroma is an uncommon dermal tumor with features that overlap with spiradenoma and cylindroma.¹ It may manifest as a solitary lesion or multiple lesions and can occur sporadically or in the context of a family history. Histologically, it must be distinguished from other intradermal basaloid neoplasms including conventional cylindroma and spiradenoma, dermal duct tumor, hidradenoma, and trichoblastoma.

When patients present with multiple cylindromas, spiradenomas, or spiradenocylindromas, physicians should consider genetic testing and review of the family history to assess for cylindromatosis gene mutations or Brooke-Spiegler syndrome. Biopsy and histologic examination are important because malignant tumors can evolve from pre-existing spiradenocylindromas, cylindromas, and spiradenomas,² with an increased risk in patients with Brooke-Spiegler syndrome.¹ Our patient declined further genetic workup but continues to follow up with dermatology for monitoring of lesions.

Dermal duct tumors are morphologic variants of poromas that are derived from sweat gland lineage and usually manifest as solitary dome-shaped papules, plaques, or nodules most often seen on acral surfaces as well as the head and neck.³ Clinically, they may be indistinguishable from spiradenocylindromas and require biopsy for histologic evaluation. They can be distinguished from spiradenocylindroma by the presence of small dermal nodules composed of cuboidal cells with ample pink cytoplasm and cuticle-lined ducts (Figure 1).

Trichoblastomas typically are deep-seated basaloid follicular neoplasms on the scalp with papillary mesenchyme resembling the normal fibrous sheath of the hair follicle, often replete with papillary mesenchymal bodies (Figure 2). There generally are no retraction spaces between its basaloid nests and the surrounding stroma, which is unlikely to contain mucin relative to basal cell carcinoma (BCC).^4,5

Adenoid cystic carcinoma is a rare salivary gland tumor that can metastasize to the skin and rarely arises as a primary skin adnexal tumor. It manifests as a slowgrowing mass that can be tender to palpation.⁶ Histologic examination shows dermal islands with cribriform blue and pink spaces. Compared to BCC, adenoid cystic carcinoma cells are enlarged and epithelioid with relatively scarce cytoplasm (Figure 3).^6,7 Adenoid cystic carcinoma can show variable growth patterns including infiltrative nests and trabeculae. Perineural invasion is common, and there is a high risk for local recurrence.⁷ First-line therapy usually is surgical, and postoperative radiotherapy may be required.^6,7

Nodular BCC commonly manifests as an enlarging nonhealing lesion on sun-exposed skin and has many subtypes, typically with arborizing telangiectases on dermoscopy. Histopathologic examination of nodular BCC reveals a nest of basaloid follicular germinative cells in the dermis with peripheral palisading and a fibromyxoid stroma (Figure 4).⁸ Patients with Brooke-Spiegler syndrome are at increased risk for nodular BCC, which may be clinically indistinguishable from spiradenoma, cylindroma, and spiradenocylindroma, necessitating histologic assessment.

The Diagnosis: Spiradenocylindroma

Shave biopsies of our patient’s lesions showed wellcircumscribed dermal nodules resembling a spiradenoma with 3 cell populations: those with lighter nuclei, darker nuclei, and scattered lymphocytes. However, the conspicuous globules of basement membrane material were reminiscent of a cylindroma. These overlapping features and the patient’s history of cylindroma were suggestive of a diagnosis of spiradenocylindroma.

Spiradenocylindroma is an uncommon dermal tumor with features that overlap with spiradenoma and cylindroma.¹ It may manifest as a solitary lesion or multiple lesions and can occur sporadically or in the context of a family history. Histologically, it must be distinguished from other intradermal basaloid neoplasms including conventional cylindroma and spiradenoma, dermal duct tumor, hidradenoma, and trichoblastoma.

When patients present with multiple cylindromas, spiradenomas, or spiradenocylindromas, physicians should consider genetic testing and review of the family history to assess for cylindromatosis gene mutations or Brooke-Spiegler syndrome. Biopsy and histologic examination are important because malignant tumors can evolve from pre-existing spiradenocylindromas, cylindromas, and spiradenomas,² with an increased risk in patients with Brooke-Spiegler syndrome.¹ Our patient declined further genetic workup but continues to follow up with dermatology for monitoring of lesions.

Dermal duct tumors are morphologic variants of poromas that are derived from sweat gland lineage and usually manifest as solitary dome-shaped papules, plaques, or nodules most often seen on acral surfaces as well as the head and neck.³ Clinically, they may be indistinguishable from spiradenocylindromas and require biopsy for histologic evaluation. They can be distinguished from spiradenocylindroma by the presence of small dermal nodules composed of cuboidal cells with ample pink cytoplasm and cuticle-lined ducts (Figure 1).

Trichoblastomas typically are deep-seated basaloid follicular neoplasms on the scalp with papillary mesenchyme resembling the normal fibrous sheath of the hair follicle, often replete with papillary mesenchymal bodies (Figure 2). There generally are no retraction spaces between its basaloid nests and the surrounding stroma, which is unlikely to contain mucin relative to basal cell carcinoma (BCC).^4,5

Adenoid cystic carcinoma is a rare salivary gland tumor that can metastasize to the skin and rarely arises as a primary skin adnexal tumor. It manifests as a slowgrowing mass that can be tender to palpation.⁶ Histologic examination shows dermal islands with cribriform blue and pink spaces. Compared to BCC, adenoid cystic carcinoma cells are enlarged and epithelioid with relatively scarce cytoplasm (Figure 3).^6,7 Adenoid cystic carcinoma can show variable growth patterns including infiltrative nests and trabeculae. Perineural invasion is common, and there is a high risk for local recurrence.⁷ First-line therapy usually is surgical, and postoperative radiotherapy may be required.^6,7

Nodular BCC commonly manifests as an enlarging nonhealing lesion on sun-exposed skin and has many subtypes, typically with arborizing telangiectases on dermoscopy. Histopathologic examination of nodular BCC reveals a nest of basaloid follicular germinative cells in the dermis with peripheral palisading and a fibromyxoid stroma (Figure 4).⁸ Patients with Brooke-Spiegler syndrome are at increased risk for nodular BCC, which may be clinically indistinguishable from spiradenoma, cylindroma, and spiradenocylindroma, necessitating histologic assessment.

To the Editor:

A 56-year-old man was referred to our Grand Rounds by another dermatologist in our health system for evaluation of a red scaly rash on the trunk that had been present for more than a year. More recently, over the course of approximately 9 months he experienced recurrent painful penile ulcers that lasted for approximately 4 weeks and then self-resolved. He had a medical history of central retinal vein occlusion, primary hyperparathyroidism, and nonspecific colitis. A family history was notable for lung cancer in the patient’s father and myelodysplastic syndrome and breast cancer in his mother; however, there was no family history of a similar rash. A bacterial culture of the penile ulcer was negative. Testing for antibodies against HIV and herpes simplex virus (HSV) types 1 and 2 was negative. Results of a serum VDRL test were nonreactive, which ruled out syphilis. The patient was treated by the referring dermatologist with azithromycin for possible chancroid without relief.

The patient was being followed by the referring dermatologist who initially was concerned for Degos disease based on clinical examination findings, prompting biopsy of a lesion on the back, which revealed vacuolar interface dermatitis, a sparse superficial perivascular lymphocytic infiltrate, and increased mucin—all highly suspicious for connective tissue disease (Figure 1). An antinuclear antibody test was positive, with a titer of 1:640. The patient was started on prednisone and referred to rheumatology; however, further evaluation by rheumatology for an autoimmune process—including anticardiolipin antibodies—was unremarkable. A few months prior to the current presentation, he also had mildly elevated liver function test results. A colonoscopy was performed, and a biopsy revealed nonspecific colitis. A biopsy of the penile ulcer also was nonspecific, showing only ulceration and acute and chronic inflammation. No epidermal interface change was seen. Results from a Grocott-Gomori methenamine-silver stain, Treponema pallidum immunostain, and HSV polymerase chain reaction were negative for fungal organisms, spirochetes, and HSV, respectively. The differential diagnosis included trauma, aphthous ulceration, and Behçet disease. Behçet disease was suspected by the referring dermatologist, and the patient was treated with colchicine, prednisone, pimecrolimus cream, and topical lidocaine; however, the lesions persisted, and he was subsequently referred to our Grand Rounds for further evaluation.

At the current presentation, physical examination revealed several small papules with white atrophic centers and erythematous rims on the trunk and extremities (Figure 2A). An ulceration was noted on the penile shaft (Figure 2B). Further evaluation for Behçet disease, including testing for pathergy and HLA-B51, was negative. Degos disease was strongly suspected clinically, and a repeat biopsy was performed of a lesion on the abdomen, which revealed central epidermal necrosis, atrophy, and parakeratosis with an underlying wedge-shaped dermal infarct surrounded by multiple small occluded dermal vessels, perivascular inflammation, and dermal edema (Figure 3). Direct immunofluorescence was performed using antibodies against IgG, IgA, IgM, fibrinogen, albumin, and C3, which was negative. These findings from direct immunofluorescence and histopathology as well as the clinical presentation were considered compatible with Degos disease. The patient was started on aspirin and pentoxifylline. Pentoxifylline 400 mg twice daily appeared to lessen some of the pain. Pain management specialists started the patient on gabapentin.

Approximately 4 months after the Grand Rounds evaluation, during which time he continued treatment with pentoxifylline, he was admitted to the hospital for intractable nausea and vomiting. His condition acutely declined due to bowel perforation, and he was started on eculizumab 1200 mg every 14 days. Because of an increased risk for meningococcal meningitis while on this medication, he also was given erythromycin 500 mg twice daily prophylactically. He was being followed by hematology for the vasculopathy, and they were planning to monitor for any disease changes with computed tomography of the chest, abdomen, and pelvis every 3 months, as well as echocardiogram every 6 months for any development of pericardial or pleural fibrosis. Approximately 1 month later, the patient was admitted to the hospital again but died after 1 week from gastrointestinal complications (approximately 22 months after the onset of the rash).

Degos disease (atrophic papulosis) is a rare small vessel vasculopathy of unknown etiology, but complement-mediated endothelial injury plays a role.^1,2 It typically occurs in the fourth decade of life, with a slight female predominance.^3,4 The skin lesions are characteristic and described as 5- to 10-mm papules with atrophic white centers and erythematous telangiectatic rims, most commonly on the upper body and typically sparing the head, palms, and soles.¹ Penile ulceration is an uncommon cutaneous feature, with only a few cases reported in the literature.^5,6 Approximately one-third of patients will have only skin lesions, but two-thirds will develop systemic involvement 1 to 2 years after onset, with the gastrointestinal tract and central nervous system most commonly involved. For those with systemic involvement, the 5-year survival rate is approximately 55%, and the most common causes of death are bowel perforation, peritonitis, and stroke.^3,4 Because some patients appear to never develop systemic complications, Theodoridis et al⁴ proposed that the disease be classified as either malignant atrophic papulosis or benign atrophic papulosis to indicate the malignant systemic form and the benign cutaneous form, respectively.

The histopathology of Degos disease changes as the lesions evolve.⁷ Early lesions show a superficial and deep perivascular and periadnexal lymphocytic infiltrate, possible interface dermatitis, and dermal mucin resembling lupus. The more fully developed lesions show a greater degree of inflammation and interface change as well as lymphocytic vasculitis. This stage also may have epidermal atrophy and early papillary dermal sclerosis resembling lichen sclerosus. The late-stage lesions, clinically observed as papules with atrophic white centers and surrounding erythema, show the classic pathology of wedge-shaped dermal sclerosis and central epidermal atrophy with surrounding hyperkeratosis. Interface dermatitis and dermal mucin can be seen in all stages, though mucin is diminished in the later stage.

Effective treatment options are limited; however, antithrombotics or compounds that facilitate blood perfusion, such as aspirin or pentoxifylline, initially can be used.¹ Eculizumab, a humanized monoclonal antibody that prevents the cleavage of C5, has been used for salvage therapy,⁸ as in our case. Treprostinil, a prostacyclin analog that causes arterial vasodilation and inhibition of platelet aggregation, has been reported to improve bowel and cutaneous lesions, functional status, and neurologic symptoms.⁹

Our case highlights important features of Degos disease. First, it is important for both the clinician and the pathologist to recognize that the histopathology of Degos disease changes as the lesions evolve. In our case, although the lesions were characteristic of Degos disease clinically, the initial biopsy was suspicious for connective tissue disease, which led to an autoimmune evaluation that ultimately was unremarkable. Recognizing that early lesions of Degos disease can resemble connective tissue disease histologically could have prevented this delay in diagnosis. However, Degos disease has been reported in association with autoimmune diseases.¹⁰ Second, although penile ulceration is uncommon, it can be a prominent cutaneous manifestation of the disease. Finally, eculizumab and treprostinil are therapeutic options that have shown some efficacy in improving symptoms and cutaneous lesions.^8,9

To the Editor:

A 56-year-old man was referred to our Grand Rounds by another dermatologist in our health system for evaluation of a red scaly rash on the trunk that had been present for more than a year. More recently, over the course of approximately 9 months he experienced recurrent painful penile ulcers that lasted for approximately 4 weeks and then self-resolved. He had a medical history of central retinal vein occlusion, primary hyperparathyroidism, and nonspecific colitis. A family history was notable for lung cancer in the patient’s father and myelodysplastic syndrome and breast cancer in his mother; however, there was no family history of a similar rash. A bacterial culture of the penile ulcer was negative. Testing for antibodies against HIV and herpes simplex virus (HSV) types 1 and 2 was negative. Results of a serum VDRL test were nonreactive, which ruled out syphilis. The patient was treated by the referring dermatologist with azithromycin for possible chancroid without relief.

The patient was being followed by the referring dermatologist who initially was concerned for Degos disease based on clinical examination findings, prompting biopsy of a lesion on the back, which revealed vacuolar interface dermatitis, a sparse superficial perivascular lymphocytic infiltrate, and increased mucin—all highly suspicious for connective tissue disease (Figure 1). An antinuclear antibody test was positive, with a titer of 1:640. The patient was started on prednisone and referred to rheumatology; however, further evaluation by rheumatology for an autoimmune process—including anticardiolipin antibodies—was unremarkable. A few months prior to the current presentation, he also had mildly elevated liver function test results. A colonoscopy was performed, and a biopsy revealed nonspecific colitis. A biopsy of the penile ulcer also was nonspecific, showing only ulceration and acute and chronic inflammation. No epidermal interface change was seen. Results from a Grocott-Gomori methenamine-silver stain, Treponema pallidum immunostain, and HSV polymerase chain reaction were negative for fungal organisms, spirochetes, and HSV, respectively. The differential diagnosis included trauma, aphthous ulceration, and Behçet disease. Behçet disease was suspected by the referring dermatologist, and the patient was treated with colchicine, prednisone, pimecrolimus cream, and topical lidocaine; however, the lesions persisted, and he was subsequently referred to our Grand Rounds for further evaluation.

At the current presentation, physical examination revealed several small papules with white atrophic centers and erythematous rims on the trunk and extremities (Figure 2A). An ulceration was noted on the penile shaft (Figure 2B). Further evaluation for Behçet disease, including testing for pathergy and HLA-B51, was negative. Degos disease was strongly suspected clinically, and a repeat biopsy was performed of a lesion on the abdomen, which revealed central epidermal necrosis, atrophy, and parakeratosis with an underlying wedge-shaped dermal infarct surrounded by multiple small occluded dermal vessels, perivascular inflammation, and dermal edema (Figure 3). Direct immunofluorescence was performed using antibodies against IgG, IgA, IgM, fibrinogen, albumin, and C3, which was negative. These findings from direct immunofluorescence and histopathology as well as the clinical presentation were considered compatible with Degos disease. The patient was started on aspirin and pentoxifylline. Pentoxifylline 400 mg twice daily appeared to lessen some of the pain. Pain management specialists started the patient on gabapentin.

Approximately 4 months after the Grand Rounds evaluation, during which time he continued treatment with pentoxifylline, he was admitted to the hospital for intractable nausea and vomiting. His condition acutely declined due to bowel perforation, and he was started on eculizumab 1200 mg every 14 days. Because of an increased risk for meningococcal meningitis while on this medication, he also was given erythromycin 500 mg twice daily prophylactically. He was being followed by hematology for the vasculopathy, and they were planning to monitor for any disease changes with computed tomography of the chest, abdomen, and pelvis every 3 months, as well as echocardiogram every 6 months for any development of pericardial or pleural fibrosis. Approximately 1 month later, the patient was admitted to the hospital again but died after 1 week from gastrointestinal complications (approximately 22 months after the onset of the rash).

Degos disease (atrophic papulosis) is a rare small vessel vasculopathy of unknown etiology, but complement-mediated endothelial injury plays a role.^1,2 It typically occurs in the fourth decade of life, with a slight female predominance.^3,4 The skin lesions are characteristic and described as 5- to 10-mm papules with atrophic white centers and erythematous telangiectatic rims, most commonly on the upper body and typically sparing the head, palms, and soles.¹ Penile ulceration is an uncommon cutaneous feature, with only a few cases reported in the literature.^5,6 Approximately one-third of patients will have only skin lesions, but two-thirds will develop systemic involvement 1 to 2 years after onset, with the gastrointestinal tract and central nervous system most commonly involved. For those with systemic involvement, the 5-year survival rate is approximately 55%, and the most common causes of death are bowel perforation, peritonitis, and stroke.^3,4 Because some patients appear to never develop systemic complications, Theodoridis et al⁴ proposed that the disease be classified as either malignant atrophic papulosis or benign atrophic papulosis to indicate the malignant systemic form and the benign cutaneous form, respectively.

The histopathology of Degos disease changes as the lesions evolve.⁷ Early lesions show a superficial and deep perivascular and periadnexal lymphocytic infiltrate, possible interface dermatitis, and dermal mucin resembling lupus. The more fully developed lesions show a greater degree of inflammation and interface change as well as lymphocytic vasculitis. This stage also may have epidermal atrophy and early papillary dermal sclerosis resembling lichen sclerosus. The late-stage lesions, clinically observed as papules with atrophic white centers and surrounding erythema, show the classic pathology of wedge-shaped dermal sclerosis and central epidermal atrophy with surrounding hyperkeratosis. Interface dermatitis and dermal mucin can be seen in all stages, though mucin is diminished in the later stage.

Effective treatment options are limited; however, antithrombotics or compounds that facilitate blood perfusion, such as aspirin or pentoxifylline, initially can be used.¹ Eculizumab, a humanized monoclonal antibody that prevents the cleavage of C5, has been used for salvage therapy,⁸ as in our case. Treprostinil, a prostacyclin analog that causes arterial vasodilation and inhibition of platelet aggregation, has been reported to improve bowel and cutaneous lesions, functional status, and neurologic symptoms.⁹

Our case highlights important features of Degos disease. First, it is important for both the clinician and the pathologist to recognize that the histopathology of Degos disease changes as the lesions evolve. In our case, although the lesions were characteristic of Degos disease clinically, the initial biopsy was suspicious for connective tissue disease, which led to an autoimmune evaluation that ultimately was unremarkable. Recognizing that early lesions of Degos disease can resemble connective tissue disease histologically could have prevented this delay in diagnosis. However, Degos disease has been reported in association with autoimmune diseases.¹⁰ Second, although penile ulceration is uncommon, it can be a prominent cutaneous manifestation of the disease. Finally, eculizumab and treprostinil are therapeutic options that have shown some efficacy in improving symptoms and cutaneous lesions.^8,9

To the Editor:

A 56-year-old man was referred to our Grand Rounds by another dermatologist in our health system for evaluation of a red scaly rash on the trunk that had been present for more than a year. More recently, over the course of approximately 9 months he experienced recurrent painful penile ulcers that lasted for approximately 4 weeks and then self-resolved. He had a medical history of central retinal vein occlusion, primary hyperparathyroidism, and nonspecific colitis. A family history was notable for lung cancer in the patient’s father and myelodysplastic syndrome and breast cancer in his mother; however, there was no family history of a similar rash. A bacterial culture of the penile ulcer was negative. Testing for antibodies against HIV and herpes simplex virus (HSV) types 1 and 2 was negative. Results of a serum VDRL test were nonreactive, which ruled out syphilis. The patient was treated by the referring dermatologist with azithromycin for possible chancroid without relief.

The patient was being followed by the referring dermatologist who initially was concerned for Degos disease based on clinical examination findings, prompting biopsy of a lesion on the back, which revealed vacuolar interface dermatitis, a sparse superficial perivascular lymphocytic infiltrate, and increased mucin—all highly suspicious for connective tissue disease (Figure 1). An antinuclear antibody test was positive, with a titer of 1:640. The patient was started on prednisone and referred to rheumatology; however, further evaluation by rheumatology for an autoimmune process—including anticardiolipin antibodies—was unremarkable. A few months prior to the current presentation, he also had mildly elevated liver function test results. A colonoscopy was performed, and a biopsy revealed nonspecific colitis. A biopsy of the penile ulcer also was nonspecific, showing only ulceration and acute and chronic inflammation. No epidermal interface change was seen. Results from a Grocott-Gomori methenamine-silver stain, Treponema pallidum immunostain, and HSV polymerase chain reaction were negative for fungal organisms, spirochetes, and HSV, respectively. The differential diagnosis included trauma, aphthous ulceration, and Behçet disease. Behçet disease was suspected by the referring dermatologist, and the patient was treated with colchicine, prednisone, pimecrolimus cream, and topical lidocaine; however, the lesions persisted, and he was subsequently referred to our Grand Rounds for further evaluation.

At the current presentation, physical examination revealed several small papules with white atrophic centers and erythematous rims on the trunk and extremities (Figure 2A). An ulceration was noted on the penile shaft (Figure 2B). Further evaluation for Behçet disease, including testing for pathergy and HLA-B51, was negative. Degos disease was strongly suspected clinically, and a repeat biopsy was performed of a lesion on the abdomen, which revealed central epidermal necrosis, atrophy, and parakeratosis with an underlying wedge-shaped dermal infarct surrounded by multiple small occluded dermal vessels, perivascular inflammation, and dermal edema (Figure 3). Direct immunofluorescence was performed using antibodies against IgG, IgA, IgM, fibrinogen, albumin, and C3, which was negative. These findings from direct immunofluorescence and histopathology as well as the clinical presentation were considered compatible with Degos disease. The patient was started on aspirin and pentoxifylline. Pentoxifylline 400 mg twice daily appeared to lessen some of the pain. Pain management specialists started the patient on gabapentin.

Approximately 4 months after the Grand Rounds evaluation, during which time he continued treatment with pentoxifylline, he was admitted to the hospital for intractable nausea and vomiting. His condition acutely declined due to bowel perforation, and he was started on eculizumab 1200 mg every 14 days. Because of an increased risk for meningococcal meningitis while on this medication, he also was given erythromycin 500 mg twice daily prophylactically. He was being followed by hematology for the vasculopathy, and they were planning to monitor for any disease changes with computed tomography of the chest, abdomen, and pelvis every 3 months, as well as echocardiogram every 6 months for any development of pericardial or pleural fibrosis. Approximately 1 month later, the patient was admitted to the hospital again but died after 1 week from gastrointestinal complications (approximately 22 months after the onset of the rash).

Degos disease (atrophic papulosis) is a rare small vessel vasculopathy of unknown etiology, but complement-mediated endothelial injury plays a role.^1,2 It typically occurs in the fourth decade of life, with a slight female predominance.^3,4 The skin lesions are characteristic and described as 5- to 10-mm papules with atrophic white centers and erythematous telangiectatic rims, most commonly on the upper body and typically sparing the head, palms, and soles.¹ Penile ulceration is an uncommon cutaneous feature, with only a few cases reported in the literature.^5,6 Approximately one-third of patients will have only skin lesions, but two-thirds will develop systemic involvement 1 to 2 years after onset, with the gastrointestinal tract and central nervous system most commonly involved. For those with systemic involvement, the 5-year survival rate is approximately 55%, and the most common causes of death are bowel perforation, peritonitis, and stroke.^3,4 Because some patients appear to never develop systemic complications, Theodoridis et al⁴ proposed that the disease be classified as either malignant atrophic papulosis or benign atrophic papulosis to indicate the malignant systemic form and the benign cutaneous form, respectively.

The histopathology of Degos disease changes as the lesions evolve.⁷ Early lesions show a superficial and deep perivascular and periadnexal lymphocytic infiltrate, possible interface dermatitis, and dermal mucin resembling lupus. The more fully developed lesions show a greater degree of inflammation and interface change as well as lymphocytic vasculitis. This stage also may have epidermal atrophy and early papillary dermal sclerosis resembling lichen sclerosus. The late-stage lesions, clinically observed as papules with atrophic white centers and surrounding erythema, show the classic pathology of wedge-shaped dermal sclerosis and central epidermal atrophy with surrounding hyperkeratosis. Interface dermatitis and dermal mucin can be seen in all stages, though mucin is diminished in the later stage.

Effective treatment options are limited; however, antithrombotics or compounds that facilitate blood perfusion, such as aspirin or pentoxifylline, initially can be used.¹ Eculizumab, a humanized monoclonal antibody that prevents the cleavage of C5, has been used for salvage therapy,⁸ as in our case. Treprostinil, a prostacyclin analog that causes arterial vasodilation and inhibition of platelet aggregation, has been reported to improve bowel and cutaneous lesions, functional status, and neurologic symptoms.⁹

Our case highlights important features of Degos disease. First, it is important for both the clinician and the pathologist to recognize that the histopathology of Degos disease changes as the lesions evolve. In our case, although the lesions were characteristic of Degos disease clinically, the initial biopsy was suspicious for connective tissue disease, which led to an autoimmune evaluation that ultimately was unremarkable. Recognizing that early lesions of Degos disease can resemble connective tissue disease histologically could have prevented this delay in diagnosis. However, Degos disease has been reported in association with autoimmune diseases.¹⁰ Second, although penile ulceration is uncommon, it can be a prominent cutaneous manifestation of the disease. Finally, eculizumab and treprostinil are therapeutic options that have shown some efficacy in improving symptoms and cutaneous lesions.^8,9

The Diagnosis: Subcutaneous Fat Necrosis

Histopathology revealed lobular panniculitis with lymphohistiocytic inflammation, lipid crystals, and calcifications in our patient (Figure). Subcutaneous fat necrosis (SCFN) was diagnosed based on these characteristic histopathologic findings. No further treatment was pursued.

Subcutaneous fat necrosis is a rare, self-limiting panniculitis that typically resolves within several weeks to months without scarring. It manifests as red or violaceous subcutaneous nodules or plaques most commonly on the buttocks, trunk, proximal arms and legs, and cheeks.¹ Histopathology reveals lobular panniculitis with dense granulomatous infiltrates of histiocytes, eosinophils, and multinucleated giant cells with needle-shaped crystals. Focal areas of fat necrosis with calcification also can be seen.²

The epidemiology of SCFN is unknown. Most cases occur in healthy full-term to postterm neonates who experience hypoxia, other prenatal stressors, or therapeutic hypothermia for the treatment of hypoxic-ischemic encephalopathy.³ Although the etiology is unclear, certain inciting factors such as local tissue hypoxia, cold exposure, meconium aspiration, maternal diabetes, preeclampsia, and mechanical pressure have been proposed. Our patient underwent hypothermic cooling protocol, and it has been suggested that the increased saturated to unsaturated fat concentration in the skin of newborns increases the melting point, thus predisposing them to fat crystalization.⁴ Cases of SCFN involving the scalp are rare; therefore, any newborns receiving hypothermic therapy for hypoxic-ischemic encephalopathy should have a thorough skin examination with possible biopsy of lesions that are characteristic of SCFN, such as red or violaceous subcutaneous nodules or plaques, for specific disease identification.

The main complication of SCFN is hypercalcemia, which occurs in approximately 50% of cases. Other serum abnormalities include hyperglycemia, hypertriglyceridemia, and thrombocytopenia, though these findings are not as well associated.⁴ Patients with associated hypercalcemia may be asymptomatic, as in our patient, but other presentations include irritability, weakness, anorexia, vomiting, renal failure, failure to thrive, and encephalopathy. Nephrocalcinosis is a common complication of severe hypercalcemia; however, there is little evidence of associated major renal dysfunction.⁵ The exact mechanism of hypercalcemia is poorly understood. A widely accepted theory postulates that a granulomatous inflammatory infiltrate upregulates 1-α-hydroxylase activity, which enzymatically converts 25-hydroxyvitamin D to its active form, 1,25-dihydroxycholecalciferol, which increases bone resorption and calcium absorption through the gastrointestinal tract and renal systems. Treatments for hypercalcemia include hyperhydration, calcium-wasting diuretics, and low calcium intake.⁶ Furthermore, calcium levels should be obtained at the time of diagnosis and 30, 45, and 60 days after the lesions resolve.⁴

Subcutaneous fat necrosis needs to be differentiated from the more severe panniculitis, sclerema neonatorum (SN), which typically affects critically ill, preterm, and small-for-gestational-age newborns. It is associated with a high mortality rate and is characterized by skin and subadjacent tissue structures. The process typically begins in the thighs, buttocks, or trunk and spreads diffusely, sparing the fat-free palms, soles, and genitalia.⁷ Although our patient was born preterm, the physical characteristics of the nodule and the lack of severe illness placed SN lower on our differential. Histopathologic differences between SCFN and SN involve the extent of tissue fibrosis and presence of inflammatory cells. Sclerema neonatorum typically manifests with thickened connective tissue with a sparse inflammatory infiltrate, including lymphocytes, histiocytes, and multinucleated giant cells.⁷ Conversely, SCFN manifests with fat necrosis with an extensive inflammatory infiltrate. It is important to be able to distinguish between these 2 conditions, as both have vastly different prognoses.

Cold panniculitis, sometimes called “popsicle panniculitis,” is a phenomenon in which cold contact with the skin causes eruption of firm, erythematous, indurated plaques at the site of exposure. This self-limiting condition typically appears hours to days after cold exposure and spontaneously resolves in a few weeks.⁸ Therapeutic hypothermic protocol treatment involves using cooling devices to lower the body temperature for a short duration. The temperature typically is lowered to approximately 32 °C to 36 °C. These temperatures are not low enough to induce cold panniculitis, which is more commonly seen in facial ice applications when managing supraventricular tachycardia in neonates.

Cephalohematoma is a birthing injury that causes blood accumulation within the subperiosteal space. During parturition, the compressive and sheering forces on the calvarium rupture the vessels passing through the periosteum, causing blood to pool slowly into the subperiostium; thus, a cephalohematoma usually manifests later at 1 to 3 days of life as localized head swelling.⁹ The bleeding typically does not cross suture lines and is primarily found in the occipital or parietal regions. The incidence has been reported to be 0.4% to 2.5% of all live births.¹⁰ Although the location of the nodule in our patient was in the occipital region, imaging and biopsy results did not show hemorrhagic findings consistent with cephalohematoma. Management of cephalohematoma mainly is observational, as the mass slowly regresses and the accumulated blood gradually is reabsorbed.

Fungal scalp infections (tinea capitis) are common in the pediatric population. The peak incidence of this infection has been reported in children aged 3 to 7 years, with Trichophyton tonsurans and Microsporum canis as the usual causative organisms.¹¹ Clinical features of tinea capitis include scaly patches with hair loss, hair loss with black pigmented dots at the follicular openings, diffuse scalp scaling with subtle hair loss, and cervical lymphadenopathy.¹² Although less common, tinea capitis can progress to a more severe form known as a kerion, which is characterized by a tender plaque with pustules and crusting. A kerion can result in permanent scarring and alopecia if left untreated.¹² In our patient, a nodule with scaling and faint erythema was observed, but no black pigmented dots at the follicular orifices were present. Therefore, a potassium hydroxide wet mount preparation used to diagnose tinea capitis was unnecessary. Systemic oral antifungal therapy such as fluconazole or terbinafine is the standard treatment for tinea capitis.

The Diagnosis: Subcutaneous Fat Necrosis

Histopathology revealed lobular panniculitis with lymphohistiocytic inflammation, lipid crystals, and calcifications in our patient (Figure). Subcutaneous fat necrosis (SCFN) was diagnosed based on these characteristic histopathologic findings. No further treatment was pursued.

Subcutaneous fat necrosis is a rare, self-limiting panniculitis that typically resolves within several weeks to months without scarring. It manifests as red or violaceous subcutaneous nodules or plaques most commonly on the buttocks, trunk, proximal arms and legs, and cheeks.¹ Histopathology reveals lobular panniculitis with dense granulomatous infiltrates of histiocytes, eosinophils, and multinucleated giant cells with needle-shaped crystals. Focal areas of fat necrosis with calcification also can be seen.²

The epidemiology of SCFN is unknown. Most cases occur in healthy full-term to postterm neonates who experience hypoxia, other prenatal stressors, or therapeutic hypothermia for the treatment of hypoxic-ischemic encephalopathy.³ Although the etiology is unclear, certain inciting factors such as local tissue hypoxia, cold exposure, meconium aspiration, maternal diabetes, preeclampsia, and mechanical pressure have been proposed. Our patient underwent hypothermic cooling protocol, and it has been suggested that the increased saturated to unsaturated fat concentration in the skin of newborns increases the melting point, thus predisposing them to fat crystalization.⁴ Cases of SCFN involving the scalp are rare; therefore, any newborns receiving hypothermic therapy for hypoxic-ischemic encephalopathy should have a thorough skin examination with possible biopsy of lesions that are characteristic of SCFN, such as red or violaceous subcutaneous nodules or plaques, for specific disease identification.

The main complication of SCFN is hypercalcemia, which occurs in approximately 50% of cases. Other serum abnormalities include hyperglycemia, hypertriglyceridemia, and thrombocytopenia, though these findings are not as well associated.⁴ Patients with associated hypercalcemia may be asymptomatic, as in our patient, but other presentations include irritability, weakness, anorexia, vomiting, renal failure, failure to thrive, and encephalopathy. Nephrocalcinosis is a common complication of severe hypercalcemia; however, there is little evidence of associated major renal dysfunction.⁵ The exact mechanism of hypercalcemia is poorly understood. A widely accepted theory postulates that a granulomatous inflammatory infiltrate upregulates 1-α-hydroxylase activity, which enzymatically converts 25-hydroxyvitamin D to its active form, 1,25-dihydroxycholecalciferol, which increases bone resorption and calcium absorption through the gastrointestinal tract and renal systems. Treatments for hypercalcemia include hyperhydration, calcium-wasting diuretics, and low calcium intake.⁶ Furthermore, calcium levels should be obtained at the time of diagnosis and 30, 45, and 60 days after the lesions resolve.⁴

Subcutaneous fat necrosis needs to be differentiated from the more severe panniculitis, sclerema neonatorum (SN), which typically affects critically ill, preterm, and small-for-gestational-age newborns. It is associated with a high mortality rate and is characterized by skin and subadjacent tissue structures. The process typically begins in the thighs, buttocks, or trunk and spreads diffusely, sparing the fat-free palms, soles, and genitalia.⁷ Although our patient was born preterm, the physical characteristics of the nodule and the lack of severe illness placed SN lower on our differential. Histopathologic differences between SCFN and SN involve the extent of tissue fibrosis and presence of inflammatory cells. Sclerema neonatorum typically manifests with thickened connective tissue with a sparse inflammatory infiltrate, including lymphocytes, histiocytes, and multinucleated giant cells.⁷ Conversely, SCFN manifests with fat necrosis with an extensive inflammatory infiltrate. It is important to be able to distinguish between these 2 conditions, as both have vastly different prognoses.

Cold panniculitis, sometimes called “popsicle panniculitis,” is a phenomenon in which cold contact with the skin causes eruption of firm, erythematous, indurated plaques at the site of exposure. This self-limiting condition typically appears hours to days after cold exposure and spontaneously resolves in a few weeks.⁸ Therapeutic hypothermic protocol treatment involves using cooling devices to lower the body temperature for a short duration. The temperature typically is lowered to approximately 32 °C to 36 °C. These temperatures are not low enough to induce cold panniculitis, which is more commonly seen in facial ice applications when managing supraventricular tachycardia in neonates.

Cephalohematoma is a birthing injury that causes blood accumulation within the subperiosteal space. During parturition, the compressive and sheering forces on the calvarium rupture the vessels passing through the periosteum, causing blood to pool slowly into the subperiostium; thus, a cephalohematoma usually manifests later at 1 to 3 days of life as localized head swelling.⁹ The bleeding typically does not cross suture lines and is primarily found in the occipital or parietal regions. The incidence has been reported to be 0.4% to 2.5% of all live births.¹⁰ Although the location of the nodule in our patient was in the occipital region, imaging and biopsy results did not show hemorrhagic findings consistent with cephalohematoma. Management of cephalohematoma mainly is observational, as the mass slowly regresses and the accumulated blood gradually is reabsorbed.

Fungal scalp infections (tinea capitis) are common in the pediatric population. The peak incidence of this infection has been reported in children aged 3 to 7 years, with Trichophyton tonsurans and Microsporum canis as the usual causative organisms.¹¹ Clinical features of tinea capitis include scaly patches with hair loss, hair loss with black pigmented dots at the follicular openings, diffuse scalp scaling with subtle hair loss, and cervical lymphadenopathy.¹² Although less common, tinea capitis can progress to a more severe form known as a kerion, which is characterized by a tender plaque with pustules and crusting. A kerion can result in permanent scarring and alopecia if left untreated.¹² In our patient, a nodule with scaling and faint erythema was observed, but no black pigmented dots at the follicular orifices were present. Therefore, a potassium hydroxide wet mount preparation used to diagnose tinea capitis was unnecessary. Systemic oral antifungal therapy such as fluconazole or terbinafine is the standard treatment for tinea capitis.

The Diagnosis: Subcutaneous Fat Necrosis

Histopathology revealed lobular panniculitis with lymphohistiocytic inflammation, lipid crystals, and calcifications in our patient (Figure). Subcutaneous fat necrosis (SCFN) was diagnosed based on these characteristic histopathologic findings. No further treatment was pursued.

Subcutaneous fat necrosis is a rare, self-limiting panniculitis that typically resolves within several weeks to months without scarring. It manifests as red or violaceous subcutaneous nodules or plaques most commonly on the buttocks, trunk, proximal arms and legs, and cheeks.¹ Histopathology reveals lobular panniculitis with dense granulomatous infiltrates of histiocytes, eosinophils, and multinucleated giant cells with needle-shaped crystals. Focal areas of fat necrosis with calcification also can be seen.²

The epidemiology of SCFN is unknown. Most cases occur in healthy full-term to postterm neonates who experience hypoxia, other prenatal stressors, or therapeutic hypothermia for the treatment of hypoxic-ischemic encephalopathy.³ Although the etiology is unclear, certain inciting factors such as local tissue hypoxia, cold exposure, meconium aspiration, maternal diabetes, preeclampsia, and mechanical pressure have been proposed. Our patient underwent hypothermic cooling protocol, and it has been suggested that the increased saturated to unsaturated fat concentration in the skin of newborns increases the melting point, thus predisposing them to fat crystalization.⁴ Cases of SCFN involving the scalp are rare; therefore, any newborns receiving hypothermic therapy for hypoxic-ischemic encephalopathy should have a thorough skin examination with possible biopsy of lesions that are characteristic of SCFN, such as red or violaceous subcutaneous nodules or plaques, for specific disease identification.

The main complication of SCFN is hypercalcemia, which occurs in approximately 50% of cases. Other serum abnormalities include hyperglycemia, hypertriglyceridemia, and thrombocytopenia, though these findings are not as well associated.⁴ Patients with associated hypercalcemia may be asymptomatic, as in our patient, but other presentations include irritability, weakness, anorexia, vomiting, renal failure, failure to thrive, and encephalopathy. Nephrocalcinosis is a common complication of severe hypercalcemia; however, there is little evidence of associated major renal dysfunction.⁵ The exact mechanism of hypercalcemia is poorly understood. A widely accepted theory postulates that a granulomatous inflammatory infiltrate upregulates 1-α-hydroxylase activity, which enzymatically converts 25-hydroxyvitamin D to its active form, 1,25-dihydroxycholecalciferol, which increases bone resorption and calcium absorption through the gastrointestinal tract and renal systems. Treatments for hypercalcemia include hyperhydration, calcium-wasting diuretics, and low calcium intake.⁶ Furthermore, calcium levels should be obtained at the time of diagnosis and 30, 45, and 60 days after the lesions resolve.⁴

Subcutaneous fat necrosis needs to be differentiated from the more severe panniculitis, sclerema neonatorum (SN), which typically affects critically ill, preterm, and small-for-gestational-age newborns. It is associated with a high mortality rate and is characterized by skin and subadjacent tissue structures. The process typically begins in the thighs, buttocks, or trunk and spreads diffusely, sparing the fat-free palms, soles, and genitalia.⁷ Although our patient was born preterm, the physical characteristics of the nodule and the lack of severe illness placed SN lower on our differential. Histopathologic differences between SCFN and SN involve the extent of tissue fibrosis and presence of inflammatory cells. Sclerema neonatorum typically manifests with thickened connective tissue with a sparse inflammatory infiltrate, including lymphocytes, histiocytes, and multinucleated giant cells.⁷ Conversely, SCFN manifests with fat necrosis with an extensive inflammatory infiltrate. It is important to be able to distinguish between these 2 conditions, as both have vastly different prognoses.

Cold panniculitis, sometimes called “popsicle panniculitis,” is a phenomenon in which cold contact with the skin causes eruption of firm, erythematous, indurated plaques at the site of exposure. This self-limiting condition typically appears hours to days after cold exposure and spontaneously resolves in a few weeks.⁸ Therapeutic hypothermic protocol treatment involves using cooling devices to lower the body temperature for a short duration. The temperature typically is lowered to approximately 32 °C to 36 °C. These temperatures are not low enough to induce cold panniculitis, which is more commonly seen in facial ice applications when managing supraventricular tachycardia in neonates.

Cephalohematoma is a birthing injury that causes blood accumulation within the subperiosteal space. During parturition, the compressive and sheering forces on the calvarium rupture the vessels passing through the periosteum, causing blood to pool slowly into the subperiostium; thus, a cephalohematoma usually manifests later at 1 to 3 days of life as localized head swelling.⁹ The bleeding typically does not cross suture lines and is primarily found in the occipital or parietal regions. The incidence has been reported to be 0.4% to 2.5% of all live births.¹⁰ Although the location of the nodule in our patient was in the occipital region, imaging and biopsy results did not show hemorrhagic findings consistent with cephalohematoma. Management of cephalohematoma mainly is observational, as the mass slowly regresses and the accumulated blood gradually is reabsorbed.

Fungal scalp infections (tinea capitis) are common in the pediatric population. The peak incidence of this infection has been reported in children aged 3 to 7 years, with Trichophyton tonsurans and Microsporum canis as the usual causative organisms.¹¹ Clinical features of tinea capitis include scaly patches with hair loss, hair loss with black pigmented dots at the follicular openings, diffuse scalp scaling with subtle hair loss, and cervical lymphadenopathy.¹² Although less common, tinea capitis can progress to a more severe form known as a kerion, which is characterized by a tender plaque with pustules and crusting. A kerion can result in permanent scarring and alopecia if left untreated.¹² In our patient, a nodule with scaling and faint erythema was observed, but no black pigmented dots at the follicular orifices were present. Therefore, a potassium hydroxide wet mount preparation used to diagnose tinea capitis was unnecessary. Systemic oral antifungal therapy such as fluconazole or terbinafine is the standard treatment for tinea capitis.

The Diagnosis: Lymphoepithelioma-like Carcinoma

Lymphoepithelioma-like carcinoma (LELC) is a rare, poorly differentiated, primary cutaneous neoplasm that occurs on sun-exposed skin, particularly on the head and neck of elderly individuals. It often manifests as an asymptomatic, slow-growing, flesh-colored or erythematous dermal nodule, though ulceration and tenderness have been reported.¹ Histopathologically, these neoplasms often are poorly circumscribed and can infiltrate surrounding subcutaneous and soft tissue. As a biphasic tumor, LELC is characterized by islands, nests, or trabeculae of epithelioid cells within the mid dermis surrounded by a dense lymphocytic infiltrate with plasma cells (Figure 1).¹ The epithelial component rarely communicates with the overlying epidermis and is composed of atypical polygonal cells with eosinophilic cytoplasm, vesicular nuclei, prominent nucleoli, and frequent mitosis.² These epithelial nests can be highlighted by pancytokeratin AE1/AE3 or other epithelial differentiation markers (eg, CAM 5.2, CK5/6, epithelial membrane antigen, high-molecular-weight cytokeratin), while the surrounding lymphocytic infiltrate consists of an admixture of T cells and B cells. Lymphoepithelioma-like carcinomas also can demonstrate sebaceous, eccrine, or follicular differentiations.³ The epithelial nests of LELC also are positive for p63 and epithelial membrane antigen.²

The usual treatment of LELC is wide local excision or Mohs micrographic surgery.¹ Despite the poorly differentiated morphology of the tumor, LELC has a generally good prognosis with low metastatic potential and few reports of local recurrence after incomplete excision.³ Patients who are not candidates for surgery as well as recalcitrant cases are managed with radiotherapy.¹

Cutaneous lymphadenoma (CL) is a benign adnexal neoplasm that manifests as a small, solitary, fleshcolored nodule usually in the head and neck region.⁴ Histologically, CL consists of well-circumscribed epithelial nests within the dermis that are peripherally outlined by palisading basaloid cells and filled with clear to eosinophilic epithelioid cells (Figure 2).5 The fibrotic tumor stroma often is infiltrated by numerous intralobular dendritic cells and lymphocytes that occasionally can be arranged in germinal center–like nodules.⁴ The lymphoepithelial nature of CL can be challenging to distinguish morphologically from LELC, and immunohistochemistry stains may be required. In CL, both the basaloid and epithelioid cells stain positive for pancytokeratin AE1/ AE3, but the peripheral palisaded basaloid cells also stain positive for BerEP4. Additionally, the fibrotic stroma can be highlighted by CD34 and the intralobular dendritic cells by S-100.⁴

Nasopharyngeal carcinoma (NPC), formerly known as lymphoepithelioma, refers to carcinoma arising within the epithelium of the nasopharynx.⁶ Endemic to China, NPC manifests as an enlarging nasopharyngeal mass, causing clinical symptoms such as nasal obstruction and epistaxis.⁷ Histologically, nonkeratinizing NPC exhibits a biphasic morphology consisting of epithelioid neoplastic cells and background lymphocytic infiltrates (Figure 3). The epithelial component consists of round to oval neoplastic cells with amphophilic to eosinophilic cytoplasm, vesicular nuclei, and prominent nucleoli.⁶ Nasopharyngeal carcinoma is associated strongly with the Epstein-Barr virus while LELC is not; thus, Epstein- Barr encoding region in situ hybridization can reliably distinguish these entities. Metastatic NPC is rare but has been reported; therefore, it is highly recommended to perform an otolaryngologic examination in addition to testing for Epstein-Barr virus reactivity as part of a complete evaluation.⁸

Cutaneous squamous cell carcinoma (SCC) is a common epidermal malignancy with multiple subtypes and variable morphology. The clinical presentation of SCC is similar to LELC—an enlarging hyperkeratotic papule or nodule on sun-exposed skin that often is ulcerated and tender.⁹ Histologically, poorly differentiated nonkeratinizing SCC can form nests and trabeculae of epithelioid cells that are stained by epithelial differentiation markers, resembling the epithelioid nests of LELC. Distinguishing between LELC and poorly differentiated SCC with robust inflammatory infiltrate can be challenging (Figure 4). In fact, some experts support LELC as an SCC variant rather than a separate entity.9 However, in contrast to LELC, the dermal nests of SCC usually maintain an epidermal connection and often are associated with an overlying area of SCC in situ or welldifferentiated SCC.³

Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma. It is the most common type of cutaneous lymphoma, accounting for almost 50% of all reported cases.¹⁰ Classic MF has an indolent course and progresses through several clinical stages. Patches and plaques characterize early stages; lymphadenopathy indicates progression to later stages in which erythroderma may develop with coalescence of patches, plaques, and tumors; and MF present in blood or lymph nodes characterizes the late stage. Each stage of MF is different histologically—from a superficial lichenoid infiltrate with exocytosis of malignant T cells in the patch stage, to more robust epidermotropism and dermal infiltrate in the plaque stage, and finally a dense dermal infiltrate in the late stage.¹¹ The rare syringotropic variant of MF clinically manifests as solitary or multiple erythematous lesions, often with overlying alopecia. Syringotropic MF uniquely exhibits folliculotropism and syringotropism along with syringometaplasia on histologic evaluation (Figure 5).¹² The syringometaplasia can be difficult to distinguish from the epithelial nests of LELC, particularly with the lymphocytic background. Immunohistochemical panels for T-cell markers can highlight aberrant T cells in syringotropic MF through their usual loss of CD5 and CD7, in comparison to normal T cells in LELC.¹¹ An elevated CD4:CD8 ratio of 4:1 and molecular analysis for T-cell receptor gene clonal rearrangements also can support the diagnosis of MF.¹²

The Diagnosis: Lymphoepithelioma-like Carcinoma

Lymphoepithelioma-like carcinoma (LELC) is a rare, poorly differentiated, primary cutaneous neoplasm that occurs on sun-exposed skin, particularly on the head and neck of elderly individuals. It often manifests as an asymptomatic, slow-growing, flesh-colored or erythematous dermal nodule, though ulceration and tenderness have been reported.¹ Histopathologically, these neoplasms often are poorly circumscribed and can infiltrate surrounding subcutaneous and soft tissue. As a biphasic tumor, LELC is characterized by islands, nests, or trabeculae of epithelioid cells within the mid dermis surrounded by a dense lymphocytic infiltrate with plasma cells (Figure 1).¹ The epithelial component rarely communicates with the overlying epidermis and is composed of atypical polygonal cells with eosinophilic cytoplasm, vesicular nuclei, prominent nucleoli, and frequent mitosis.² These epithelial nests can be highlighted by pancytokeratin AE1/AE3 or other epithelial differentiation markers (eg, CAM 5.2, CK5/6, epithelial membrane antigen, high-molecular-weight cytokeratin), while the surrounding lymphocytic infiltrate consists of an admixture of T cells and B cells. Lymphoepithelioma-like carcinomas also can demonstrate sebaceous, eccrine, or follicular differentiations.³ The epithelial nests of LELC also are positive for p63 and epithelial membrane antigen.²

The usual treatment of LELC is wide local excision or Mohs micrographic surgery.¹ Despite the poorly differentiated morphology of the tumor, LELC has a generally good prognosis with low metastatic potential and few reports of local recurrence after incomplete excision.³ Patients who are not candidates for surgery as well as recalcitrant cases are managed with radiotherapy.¹

Cutaneous lymphadenoma (CL) is a benign adnexal neoplasm that manifests as a small, solitary, fleshcolored nodule usually in the head and neck region.⁴ Histologically, CL consists of well-circumscribed epithelial nests within the dermis that are peripherally outlined by palisading basaloid cells and filled with clear to eosinophilic epithelioid cells (Figure 2).5 The fibrotic tumor stroma often is infiltrated by numerous intralobular dendritic cells and lymphocytes that occasionally can be arranged in germinal center–like nodules.⁴ The lymphoepithelial nature of CL can be challenging to distinguish morphologically from LELC, and immunohistochemistry stains may be required. In CL, both the basaloid and epithelioid cells stain positive for pancytokeratin AE1/ AE3, but the peripheral palisaded basaloid cells also stain positive for BerEP4. Additionally, the fibrotic stroma can be highlighted by CD34 and the intralobular dendritic cells by S-100.⁴

Nasopharyngeal carcinoma (NPC), formerly known as lymphoepithelioma, refers to carcinoma arising within the epithelium of the nasopharynx.⁶ Endemic to China, NPC manifests as an enlarging nasopharyngeal mass, causing clinical symptoms such as nasal obstruction and epistaxis.⁷ Histologically, nonkeratinizing NPC exhibits a biphasic morphology consisting of epithelioid neoplastic cells and background lymphocytic infiltrates (Figure 3). The epithelial component consists of round to oval neoplastic cells with amphophilic to eosinophilic cytoplasm, vesicular nuclei, and prominent nucleoli.⁶ Nasopharyngeal carcinoma is associated strongly with the Epstein-Barr virus while LELC is not; thus, Epstein- Barr encoding region in situ hybridization can reliably distinguish these entities. Metastatic NPC is rare but has been reported; therefore, it is highly recommended to perform an otolaryngologic examination in addition to testing for Epstein-Barr virus reactivity as part of a complete evaluation.⁸

Cutaneous squamous cell carcinoma (SCC) is a common epidermal malignancy with multiple subtypes and variable morphology. The clinical presentation of SCC is similar to LELC—an enlarging hyperkeratotic papule or nodule on sun-exposed skin that often is ulcerated and tender.⁹ Histologically, poorly differentiated nonkeratinizing SCC can form nests and trabeculae of epithelioid cells that are stained by epithelial differentiation markers, resembling the epithelioid nests of LELC. Distinguishing between LELC and poorly differentiated SCC with robust inflammatory infiltrate can be challenging (Figure 4). In fact, some experts support LELC as an SCC variant rather than a separate entity.9 However, in contrast to LELC, the dermal nests of SCC usually maintain an epidermal connection and often are associated with an overlying area of SCC in situ or welldifferentiated SCC.³

Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma. It is the most common type of cutaneous lymphoma, accounting for almost 50% of all reported cases.¹⁰ Classic MF has an indolent course and progresses through several clinical stages. Patches and plaques characterize early stages; lymphadenopathy indicates progression to later stages in which erythroderma may develop with coalescence of patches, plaques, and tumors; and MF present in blood or lymph nodes characterizes the late stage. Each stage of MF is different histologically—from a superficial lichenoid infiltrate with exocytosis of malignant T cells in the patch stage, to more robust epidermotropism and dermal infiltrate in the plaque stage, and finally a dense dermal infiltrate in the late stage.¹¹ The rare syringotropic variant of MF clinically manifests as solitary or multiple erythematous lesions, often with overlying alopecia. Syringotropic MF uniquely exhibits folliculotropism and syringotropism along with syringometaplasia on histologic evaluation (Figure 5).¹² The syringometaplasia can be difficult to distinguish from the epithelial nests of LELC, particularly with the lymphocytic background. Immunohistochemical panels for T-cell markers can highlight aberrant T cells in syringotropic MF through their usual loss of CD5 and CD7, in comparison to normal T cells in LELC.¹¹ An elevated CD4:CD8 ratio of 4:1 and molecular analysis for T-cell receptor gene clonal rearrangements also can support the diagnosis of MF.¹²

The Diagnosis: Lymphoepithelioma-like Carcinoma

Lymphoepithelioma-like carcinoma (LELC) is a rare, poorly differentiated, primary cutaneous neoplasm that occurs on sun-exposed skin, particularly on the head and neck of elderly individuals. It often manifests as an asymptomatic, slow-growing, flesh-colored or erythematous dermal nodule, though ulceration and tenderness have been reported.¹ Histopathologically, these neoplasms often are poorly circumscribed and can infiltrate surrounding subcutaneous and soft tissue. As a biphasic tumor, LELC is characterized by islands, nests, or trabeculae of epithelioid cells within the mid dermis surrounded by a dense lymphocytic infiltrate with plasma cells (Figure 1).¹ The epithelial component rarely communicates with the overlying epidermis and is composed of atypical polygonal cells with eosinophilic cytoplasm, vesicular nuclei, prominent nucleoli, and frequent mitosis.² These epithelial nests can be highlighted by pancytokeratin AE1/AE3 or other epithelial differentiation markers (eg, CAM 5.2, CK5/6, epithelial membrane antigen, high-molecular-weight cytokeratin), while the surrounding lymphocytic infiltrate consists of an admixture of T cells and B cells. Lymphoepithelioma-like carcinomas also can demonstrate sebaceous, eccrine, or follicular differentiations.³ The epithelial nests of LELC also are positive for p63 and epithelial membrane antigen.²

The usual treatment of LELC is wide local excision or Mohs micrographic surgery.¹ Despite the poorly differentiated morphology of the tumor, LELC has a generally good prognosis with low metastatic potential and few reports of local recurrence after incomplete excision.³ Patients who are not candidates for surgery as well as recalcitrant cases are managed with radiotherapy.¹

Cutaneous lymphadenoma (CL) is a benign adnexal neoplasm that manifests as a small, solitary, fleshcolored nodule usually in the head and neck region.⁴ Histologically, CL consists of well-circumscribed epithelial nests within the dermis that are peripherally outlined by palisading basaloid cells and filled with clear to eosinophilic epithelioid cells (Figure 2).5 The fibrotic tumor stroma often is infiltrated by numerous intralobular dendritic cells and lymphocytes that occasionally can be arranged in germinal center–like nodules.⁴ The lymphoepithelial nature of CL can be challenging to distinguish morphologically from LELC, and immunohistochemistry stains may be required. In CL, both the basaloid and epithelioid cells stain positive for pancytokeratin AE1/ AE3, but the peripheral palisaded basaloid cells also stain positive for BerEP4. Additionally, the fibrotic stroma can be highlighted by CD34 and the intralobular dendritic cells by S-100.⁴

Nasopharyngeal carcinoma (NPC), formerly known as lymphoepithelioma, refers to carcinoma arising within the epithelium of the nasopharynx.⁶ Endemic to China, NPC manifests as an enlarging nasopharyngeal mass, causing clinical symptoms such as nasal obstruction and epistaxis.⁷ Histologically, nonkeratinizing NPC exhibits a biphasic morphology consisting of epithelioid neoplastic cells and background lymphocytic infiltrates (Figure 3). The epithelial component consists of round to oval neoplastic cells with amphophilic to eosinophilic cytoplasm, vesicular nuclei, and prominent nucleoli.⁶ Nasopharyngeal carcinoma is associated strongly with the Epstein-Barr virus while LELC is not; thus, Epstein- Barr encoding region in situ hybridization can reliably distinguish these entities. Metastatic NPC is rare but has been reported; therefore, it is highly recommended to perform an otolaryngologic examination in addition to testing for Epstein-Barr virus reactivity as part of a complete evaluation.⁸

Cutaneous squamous cell carcinoma (SCC) is a common epidermal malignancy with multiple subtypes and variable morphology. The clinical presentation of SCC is similar to LELC—an enlarging hyperkeratotic papule or nodule on sun-exposed skin that often is ulcerated and tender.⁹ Histologically, poorly differentiated nonkeratinizing SCC can form nests and trabeculae of epithelioid cells that are stained by epithelial differentiation markers, resembling the epithelioid nests of LELC. Distinguishing between LELC and poorly differentiated SCC with robust inflammatory infiltrate can be challenging (Figure 4). In fact, some experts support LELC as an SCC variant rather than a separate entity.9 However, in contrast to LELC, the dermal nests of SCC usually maintain an epidermal connection and often are associated with an overlying area of SCC in situ or welldifferentiated SCC.³

Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma. It is the most common type of cutaneous lymphoma, accounting for almost 50% of all reported cases.¹⁰ Classic MF has an indolent course and progresses through several clinical stages. Patches and plaques characterize early stages; lymphadenopathy indicates progression to later stages in which erythroderma may develop with coalescence of patches, plaques, and tumors; and MF present in blood or lymph nodes characterizes the late stage. Each stage of MF is different histologically—from a superficial lichenoid infiltrate with exocytosis of malignant T cells in the patch stage, to more robust epidermotropism and dermal infiltrate in the plaque stage, and finally a dense dermal infiltrate in the late stage.¹¹ The rare syringotropic variant of MF clinically manifests as solitary or multiple erythematous lesions, often with overlying alopecia. Syringotropic MF uniquely exhibits folliculotropism and syringotropism along with syringometaplasia on histologic evaluation (Figure 5).¹² The syringometaplasia can be difficult to distinguish from the epithelial nests of LELC, particularly with the lymphocytic background. Immunohistochemical panels for T-cell markers can highlight aberrant T cells in syringotropic MF through their usual loss of CD5 and CD7, in comparison to normal T cells in LELC.¹¹ An elevated CD4:CD8 ratio of 4:1 and molecular analysis for T-cell receptor gene clonal rearrangements also can support the diagnosis of MF.¹²

To the Editor:

Sporotrichosis refers to a subacute to chronic fungal infection that usually involves the cutaneous and subcutaneous tissues and is caused by the introduction of Sporothrix, a dimorphic fungus, through the skin. We present a case of chronic atypical lymphocutaneous sporotrichosis.

A 46-year-old man presented to the outpatient dermatology clinic for follow-up for a rash on the right leg that spread to the thigh and became painful and pruritic. It initially developed 8 years prior to the current presentation after he sustained trauma to the leg from an electroshock weapon. One year prior to the current presentation, he had presented to the emergency department and was prescribed doxycycline 100 mg twice daily for 7 days as well as bacitracin ointment. He also was instructed to follow up with dermatology, but a lack of health insurance and other socioeconomic barriers prevented him from seeking dermatologic care. Nine months later, he again presented to the emergency department due to a motor vehicle accident. Computed tomography (CT) of the right leg revealed exophytic dermal masses, inflammatory stranding of the subcutaneous tissue, and right inguinal lymph nodes measuring up to 1.4 cm; there was no osteoarticular involvement. At that time, the patient was applying gentian violet to the skin lesions and taking hydroxyzine 50 mg 3 times daily as needed for pruritus with minimal relief. Financial support was provided for follow-up with dermatology, which occurred almost 5 months later.

At the current presentation, physical examination revealed a large annular plaque with verrucous, scaly, erythematous borders and a hypopigmented atrophic center extending from the medial aspect of the right leg to the posterior thigh. Numerous pink, scaly, crusted nodules were scattered primarily along the periphery, with some evidence of draining sinus tracts. In addition, a fibrotic pink linear plaque extended from the medial right leg to the popliteal fossa, consistent with a keloid. Violet staining along the periphery of the lesion also was appreciated secondary to the application of topical gentian violet (Figure 1).

Based on the chronic history and morphology, a diagnosis of a chronic fungal or atypical mycobacterial infection was favored. In particular, chromoblastomycosis, cutaneous tuberculosis (eg, scrofuloderma, lupus vulgaris, tuberculosis verrucosa cutis), and atypical mycobacterial infection were highest on the differential, as these conditions often exhibit annular, nodular, verrucous, and/or atrophic lesions. The nodularity, crusting, and draining sinus tracts also raised the possibility of mycetoma. Given the extension of the lesion from the lower to upper leg, a sporotrichoid infection also was considered but was thought to be less likely based on the annular configuration.

Two 4-mm punch biopsies were taken from a peripheral nodule—one for routine histology and another for bacterial, fungal, and mycobacterial cultures. An ­interferon-gamma release assay also was ordered to evaluate for immune responses indicative of prior Mycobacterium tuberculosis infection, but the patient did not obtain this for unknown reasons. Histology demonstrated pseudoepitheliomatous hyperplasia and necrotizing granulomas, which suggested an infectious etiology, but no organisms were identified on tissue staining and all cultures were negative for growth at 6 weeks. The patient was asked to return at that point, and 4 additional scouting biopsies were performed and sent for routine histology, M tuberculosis nucleic acid amplification testing, and microbiologic cultures (ie, bacterial, mycobacterial, fungal, nocardia, actinomycetes). Within 1 week, a filamentous organism with pigmentation visible on the front and back of a Sabouraud dextrose agar plate was identified on fungal culture (Figure 2). Microscopic evaluation of this mold with lactophenol blue stain revealed thin septate hyphae with conidiophores arising at right angles that bore clusters of microconidia (Figure 3). Sequencing analysis ultimately identified this organism as Sporothrix schenckii. Routine histology demonstrated pseudoepitheliomatous hyperplasia with scattered intraepidermal collections of neutrophils (Figure 4). The dermis showed a dense, superficial, and deep infiltrate composed of lymphocytes, histiocytes, and plasma cells with occasional neutrophils and eosinophils. A Grocott-Gomori methenamine-silver stain revealed a cluster of ovoid yeast forms within the stratum corneum (Figure 5). The patient was referred to infectious disease for follow-up and treatment.

The patient later visited a community clinic providing dermatologic care for patients without insurance. He was started on itraconazole 200 mg daily for a total of 6 months until dermatologic clearance of the cutaneous lesions was observed. He was followed by the clinic with laboratory tests including a liver function test. At follow-up 8 months later, a repeat biopsy was performed to ensure histologic clearance of the sporotrichosis, which revealed a dermal scar and no evidence of residual infection.

Sporothrix schenckii was first isolated in 1898 by Benjamin Schenck, a student at Johns Hopkins Medicine (Baltimore, Maryland), and identified by a mycologist as sporotricha.¹ Species within the genus Sporothrix are unique in that the fungi are both dimorphic (growing as a mold at 25 °C but as a yeast at 37 °C) and dematiaceous (dark pigmentation from melanin is visible on inspection of the anterior and reverse sides of culture plates). Infection usually occurs when cutaneous or subcutaneous tissues are exposed to the fungus via microabrasions; activities thought to contribute to exposure include gardening, agricultural work, animal husbandry, and feline scratches.² Although skin trauma frequently is considered the primary route of infection, patient recall is variable, with one study noting that only 37.7% of patients recalled trauma and another study similarly demonstrating a patient recall rate of 25%.^3,4

Lymphocutaneous sporotrichosis is the most common presentation of the fungal infection,⁵ and clinical cases may be classified into 1 of 4 categories: (1) lymphangitic lesions—papules at the site of inoculation with spread along the lymphatic channels; (2) localized (fixed) cutaneous lesions—1 or 2 lesions at the inoculation site; (3) disseminated (multifocal) cutaneous lesions; and (4) extracutaneous lesions.⁶ Extracutaneous manifestations of this infection most notably have been reported as pulmonary disease through inhalation of conidia or through dissemination in immunocompromised hosts.⁷ Our patient’s infection was categorized as lymphangitic lesions due to spread from the lower to upper leg, albeit in a highly atypical, annular fashion. A review of systems was otherwise negative, and CT ruled out osteoarticular involvement.

In addition to socioeconomic barriers, several factors contributed to a delayed diagnosis in this patient including the annular presentation with central hypopigmentation and atrophy, negative initial microbiological cultures and lack of visualization of organisms on histopathology, and the consequent need for repeat biopsies. For lymphocutaneous sporotrichosis, the typical presentation consists of a papule or ulcerated nodule at the site of inoculation with subsequent linear spread along lymphatic channels. This classic sporotrichoid pattern is a key diagnostic clue for identifying sporotrichosis but was absent at the time our patient presented for medical care. Rather, the sporotrichoid spread seemed to have occurred in a centrifugal fashion up the leg. Few case reports have documented an annular presentation of lymphocutaneous sporotrichosis,^8-13 and one report described central atrophy and hypopigmentation.¹⁰ Pain and pruritus, which were present in our patient, rarely are documented.⁹ Finally, the diagnosis of cutaneous fungal infections may require multiple biopsies due to the variable abundance of viable organisms in tissue specimens as well as the fastidious growth characteristics of these organisms. Furthermore, sensitivity often is low for both fungal and mycobacterial cultures, and cultures may take days to weeks to yield growth.^14,15 For these reasons, empiric therapy and repeat biopsies often are pursued if clinical suspicion is high enough.¹⁶ Our patient returned for multiple scouting biopsies after the initial tissue culture was negative and was even considered for empiric treatment against Mycobacterium prior to positive fungal cultures.

Another unique aspect of our case was the presence of a keloid. It is difficult to know if this keloid was secondary to the trauma the patient sustained in the inciting incident or formed from the fungal infection. Interestingly, it has been hypothesized that fungal infections may contribute to keloid and hypertrophic scar formation.¹⁷ In a case series of 3 patients with either keloids or hypertrophic scars and concomitant tinea infection, there was notable improvement in the appearance of the scars 2 weeks after beginning itraconazole therapy.¹⁷ However, it is not yet known if a fungal infection can contribute to the pathogenesis of keloid formation.

As with other aspects of this case, the length of time the patient went without diagnosis and treatment was unusual and may help explain the atypical presentation. Although the incubation period for S schenckii can vary, most reports identify patients as seeking medical attention within 1 year of rash onset.^18-20 In our case, the patient was not diagnosed until 8 years after his symptoms began, requiring multiple referrals, multiple health system touchpoints, and an institution-specific financial aid program. As such, this case also highlights the potential need for a multidisciplinary team approach when caring for patients with poor access to health care.

In conclusion, this case illustrates a unique presentation of lymphocutaneous sporotrichosis that may mimic other chronic infections and result in delayed diagnosis. Although lymphangitic sporotrichosis generally is recognized as having a linear distribution, mounting evidence from this report and others suggests an annular presentation also is possible. Pruritus or pain is rare but should not preclude a diagnosis of sporotrichosis if present. For patients with limited access to health care resources, it is especially important to involve multiple members of the health care team, including social workers and specialists, to prevent a protracted and severe course of disease.

To the Editor:

Sporotrichosis refers to a subacute to chronic fungal infection that usually involves the cutaneous and subcutaneous tissues and is caused by the introduction of Sporothrix, a dimorphic fungus, through the skin. We present a case of chronic atypical lymphocutaneous sporotrichosis.

A 46-year-old man presented to the outpatient dermatology clinic for follow-up for a rash on the right leg that spread to the thigh and became painful and pruritic. It initially developed 8 years prior to the current presentation after he sustained trauma to the leg from an electroshock weapon. One year prior to the current presentation, he had presented to the emergency department and was prescribed doxycycline 100 mg twice daily for 7 days as well as bacitracin ointment. He also was instructed to follow up with dermatology, but a lack of health insurance and other socioeconomic barriers prevented him from seeking dermatologic care. Nine months later, he again presented to the emergency department due to a motor vehicle accident. Computed tomography (CT) of the right leg revealed exophytic dermal masses, inflammatory stranding of the subcutaneous tissue, and right inguinal lymph nodes measuring up to 1.4 cm; there was no osteoarticular involvement. At that time, the patient was applying gentian violet to the skin lesions and taking hydroxyzine 50 mg 3 times daily as needed for pruritus with minimal relief. Financial support was provided for follow-up with dermatology, which occurred almost 5 months later.

At the current presentation, physical examination revealed a large annular plaque with verrucous, scaly, erythematous borders and a hypopigmented atrophic center extending from the medial aspect of the right leg to the posterior thigh. Numerous pink, scaly, crusted nodules were scattered primarily along the periphery, with some evidence of draining sinus tracts. In addition, a fibrotic pink linear plaque extended from the medial right leg to the popliteal fossa, consistent with a keloid. Violet staining along the periphery of the lesion also was appreciated secondary to the application of topical gentian violet (Figure 1).

Based on the chronic history and morphology, a diagnosis of a chronic fungal or atypical mycobacterial infection was favored. In particular, chromoblastomycosis, cutaneous tuberculosis (eg, scrofuloderma, lupus vulgaris, tuberculosis verrucosa cutis), and atypical mycobacterial infection were highest on the differential, as these conditions often exhibit annular, nodular, verrucous, and/or atrophic lesions. The nodularity, crusting, and draining sinus tracts also raised the possibility of mycetoma. Given the extension of the lesion from the lower to upper leg, a sporotrichoid infection also was considered but was thought to be less likely based on the annular configuration.

Two 4-mm punch biopsies were taken from a peripheral nodule—one for routine histology and another for bacterial, fungal, and mycobacterial cultures. An ­interferon-gamma release assay also was ordered to evaluate for immune responses indicative of prior Mycobacterium tuberculosis infection, but the patient did not obtain this for unknown reasons. Histology demonstrated pseudoepitheliomatous hyperplasia and necrotizing granulomas, which suggested an infectious etiology, but no organisms were identified on tissue staining and all cultures were negative for growth at 6 weeks. The patient was asked to return at that point, and 4 additional scouting biopsies were performed and sent for routine histology, M tuberculosis nucleic acid amplification testing, and microbiologic cultures (ie, bacterial, mycobacterial, fungal, nocardia, actinomycetes). Within 1 week, a filamentous organism with pigmentation visible on the front and back of a Sabouraud dextrose agar plate was identified on fungal culture (Figure 2). Microscopic evaluation of this mold with lactophenol blue stain revealed thin septate hyphae with conidiophores arising at right angles that bore clusters of microconidia (Figure 3). Sequencing analysis ultimately identified this organism as Sporothrix schenckii. Routine histology demonstrated pseudoepitheliomatous hyperplasia with scattered intraepidermal collections of neutrophils (Figure 4). The dermis showed a dense, superficial, and deep infiltrate composed of lymphocytes, histiocytes, and plasma cells with occasional neutrophils and eosinophils. A Grocott-Gomori methenamine-silver stain revealed a cluster of ovoid yeast forms within the stratum corneum (Figure 5). The patient was referred to infectious disease for follow-up and treatment.

The patient later visited a community clinic providing dermatologic care for patients without insurance. He was started on itraconazole 200 mg daily for a total of 6 months until dermatologic clearance of the cutaneous lesions was observed. He was followed by the clinic with laboratory tests including a liver function test. At follow-up 8 months later, a repeat biopsy was performed to ensure histologic clearance of the sporotrichosis, which revealed a dermal scar and no evidence of residual infection.

Sporothrix schenckii was first isolated in 1898 by Benjamin Schenck, a student at Johns Hopkins Medicine (Baltimore, Maryland), and identified by a mycologist as sporotricha.¹ Species within the genus Sporothrix are unique in that the fungi are both dimorphic (growing as a mold at 25 °C but as a yeast at 37 °C) and dematiaceous (dark pigmentation from melanin is visible on inspection of the anterior and reverse sides of culture plates). Infection usually occurs when cutaneous or subcutaneous tissues are exposed to the fungus via microabrasions; activities thought to contribute to exposure include gardening, agricultural work, animal husbandry, and feline scratches.² Although skin trauma frequently is considered the primary route of infection, patient recall is variable, with one study noting that only 37.7% of patients recalled trauma and another study similarly demonstrating a patient recall rate of 25%.^3,4

Lymphocutaneous sporotrichosis is the most common presentation of the fungal infection,⁵ and clinical cases may be classified into 1 of 4 categories: (1) lymphangitic lesions—papules at the site of inoculation with spread along the lymphatic channels; (2) localized (fixed) cutaneous lesions—1 or 2 lesions at the inoculation site; (3) disseminated (multifocal) cutaneous lesions; and (4) extracutaneous lesions.⁶ Extracutaneous manifestations of this infection most notably have been reported as pulmonary disease through inhalation of conidia or through dissemination in immunocompromised hosts.⁷ Our patient’s infection was categorized as lymphangitic lesions due to spread from the lower to upper leg, albeit in a highly atypical, annular fashion. A review of systems was otherwise negative, and CT ruled out osteoarticular involvement.

In addition to socioeconomic barriers, several factors contributed to a delayed diagnosis in this patient including the annular presentation with central hypopigmentation and atrophy, negative initial microbiological cultures and lack of visualization of organisms on histopathology, and the consequent need for repeat biopsies. For lymphocutaneous sporotrichosis, the typical presentation consists of a papule or ulcerated nodule at the site of inoculation with subsequent linear spread along lymphatic channels. This classic sporotrichoid pattern is a key diagnostic clue for identifying sporotrichosis but was absent at the time our patient presented for medical care. Rather, the sporotrichoid spread seemed to have occurred in a centrifugal fashion up the leg. Few case reports have documented an annular presentation of lymphocutaneous sporotrichosis,^8-13 and one report described central atrophy and hypopigmentation.¹⁰ Pain and pruritus, which were present in our patient, rarely are documented.⁹ Finally, the diagnosis of cutaneous fungal infections may require multiple biopsies due to the variable abundance of viable organisms in tissue specimens as well as the fastidious growth characteristics of these organisms. Furthermore, sensitivity often is low for both fungal and mycobacterial cultures, and cultures may take days to weeks to yield growth.^14,15 For these reasons, empiric therapy and repeat biopsies often are pursued if clinical suspicion is high enough.¹⁶ Our patient returned for multiple scouting biopsies after the initial tissue culture was negative and was even considered for empiric treatment against Mycobacterium prior to positive fungal cultures.

Another unique aspect of our case was the presence of a keloid. It is difficult to know if this keloid was secondary to the trauma the patient sustained in the inciting incident or formed from the fungal infection. Interestingly, it has been hypothesized that fungal infections may contribute to keloid and hypertrophic scar formation.¹⁷ In a case series of 3 patients with either keloids or hypertrophic scars and concomitant tinea infection, there was notable improvement in the appearance of the scars 2 weeks after beginning itraconazole therapy.¹⁷ However, it is not yet known if a fungal infection can contribute to the pathogenesis of keloid formation.

As with other aspects of this case, the length of time the patient went without diagnosis and treatment was unusual and may help explain the atypical presentation. Although the incubation period for S schenckii can vary, most reports identify patients as seeking medical attention within 1 year of rash onset.^18-20 In our case, the patient was not diagnosed until 8 years after his symptoms began, requiring multiple referrals, multiple health system touchpoints, and an institution-specific financial aid program. As such, this case also highlights the potential need for a multidisciplinary team approach when caring for patients with poor access to health care.

In conclusion, this case illustrates a unique presentation of lymphocutaneous sporotrichosis that may mimic other chronic infections and result in delayed diagnosis. Although lymphangitic sporotrichosis generally is recognized as having a linear distribution, mounting evidence from this report and others suggests an annular presentation also is possible. Pruritus or pain is rare but should not preclude a diagnosis of sporotrichosis if present. For patients with limited access to health care resources, it is especially important to involve multiple members of the health care team, including social workers and specialists, to prevent a protracted and severe course of disease.

To the Editor:

Sporotrichosis refers to a subacute to chronic fungal infection that usually involves the cutaneous and subcutaneous tissues and is caused by the introduction of Sporothrix, a dimorphic fungus, through the skin. We present a case of chronic atypical lymphocutaneous sporotrichosis.

A 46-year-old man presented to the outpatient dermatology clinic for follow-up for a rash on the right leg that spread to the thigh and became painful and pruritic. It initially developed 8 years prior to the current presentation after he sustained trauma to the leg from an electroshock weapon. One year prior to the current presentation, he had presented to the emergency department and was prescribed doxycycline 100 mg twice daily for 7 days as well as bacitracin ointment. He also was instructed to follow up with dermatology, but a lack of health insurance and other socioeconomic barriers prevented him from seeking dermatologic care. Nine months later, he again presented to the emergency department due to a motor vehicle accident. Computed tomography (CT) of the right leg revealed exophytic dermal masses, inflammatory stranding of the subcutaneous tissue, and right inguinal lymph nodes measuring up to 1.4 cm; there was no osteoarticular involvement. At that time, the patient was applying gentian violet to the skin lesions and taking hydroxyzine 50 mg 3 times daily as needed for pruritus with minimal relief. Financial support was provided for follow-up with dermatology, which occurred almost 5 months later.

At the current presentation, physical examination revealed a large annular plaque with verrucous, scaly, erythematous borders and a hypopigmented atrophic center extending from the medial aspect of the right leg to the posterior thigh. Numerous pink, scaly, crusted nodules were scattered primarily along the periphery, with some evidence of draining sinus tracts. In addition, a fibrotic pink linear plaque extended from the medial right leg to the popliteal fossa, consistent with a keloid. Violet staining along the periphery of the lesion also was appreciated secondary to the application of topical gentian violet (Figure 1).

Based on the chronic history and morphology, a diagnosis of a chronic fungal or atypical mycobacterial infection was favored. In particular, chromoblastomycosis, cutaneous tuberculosis (eg, scrofuloderma, lupus vulgaris, tuberculosis verrucosa cutis), and atypical mycobacterial infection were highest on the differential, as these conditions often exhibit annular, nodular, verrucous, and/or atrophic lesions. The nodularity, crusting, and draining sinus tracts also raised the possibility of mycetoma. Given the extension of the lesion from the lower to upper leg, a sporotrichoid infection also was considered but was thought to be less likely based on the annular configuration.

Two 4-mm punch biopsies were taken from a peripheral nodule—one for routine histology and another for bacterial, fungal, and mycobacterial cultures. An ­interferon-gamma release assay also was ordered to evaluate for immune responses indicative of prior Mycobacterium tuberculosis infection, but the patient did not obtain this for unknown reasons. Histology demonstrated pseudoepitheliomatous hyperplasia and necrotizing granulomas, which suggested an infectious etiology, but no organisms were identified on tissue staining and all cultures were negative for growth at 6 weeks. The patient was asked to return at that point, and 4 additional scouting biopsies were performed and sent for routine histology, M tuberculosis nucleic acid amplification testing, and microbiologic cultures (ie, bacterial, mycobacterial, fungal, nocardia, actinomycetes). Within 1 week, a filamentous organism with pigmentation visible on the front and back of a Sabouraud dextrose agar plate was identified on fungal culture (Figure 2). Microscopic evaluation of this mold with lactophenol blue stain revealed thin septate hyphae with conidiophores arising at right angles that bore clusters of microconidia (Figure 3). Sequencing analysis ultimately identified this organism as Sporothrix schenckii. Routine histology demonstrated pseudoepitheliomatous hyperplasia with scattered intraepidermal collections of neutrophils (Figure 4). The dermis showed a dense, superficial, and deep infiltrate composed of lymphocytes, histiocytes, and plasma cells with occasional neutrophils and eosinophils. A Grocott-Gomori methenamine-silver stain revealed a cluster of ovoid yeast forms within the stratum corneum (Figure 5). The patient was referred to infectious disease for follow-up and treatment.

The patient later visited a community clinic providing dermatologic care for patients without insurance. He was started on itraconazole 200 mg daily for a total of 6 months until dermatologic clearance of the cutaneous lesions was observed. He was followed by the clinic with laboratory tests including a liver function test. At follow-up 8 months later, a repeat biopsy was performed to ensure histologic clearance of the sporotrichosis, which revealed a dermal scar and no evidence of residual infection.

Sporothrix schenckii was first isolated in 1898 by Benjamin Schenck, a student at Johns Hopkins Medicine (Baltimore, Maryland), and identified by a mycologist as sporotricha.¹ Species within the genus Sporothrix are unique in that the fungi are both dimorphic (growing as a mold at 25 °C but as a yeast at 37 °C) and dematiaceous (dark pigmentation from melanin is visible on inspection of the anterior and reverse sides of culture plates). Infection usually occurs when cutaneous or subcutaneous tissues are exposed to the fungus via microabrasions; activities thought to contribute to exposure include gardening, agricultural work, animal husbandry, and feline scratches.² Although skin trauma frequently is considered the primary route of infection, patient recall is variable, with one study noting that only 37.7% of patients recalled trauma and another study similarly demonstrating a patient recall rate of 25%.^3,4

Lymphocutaneous sporotrichosis is the most common presentation of the fungal infection,⁵ and clinical cases may be classified into 1 of 4 categories: (1) lymphangitic lesions—papules at the site of inoculation with spread along the lymphatic channels; (2) localized (fixed) cutaneous lesions—1 or 2 lesions at the inoculation site; (3) disseminated (multifocal) cutaneous lesions; and (4) extracutaneous lesions.⁶ Extracutaneous manifestations of this infection most notably have been reported as pulmonary disease through inhalation of conidia or through dissemination in immunocompromised hosts.⁷ Our patient’s infection was categorized as lymphangitic lesions due to spread from the lower to upper leg, albeit in a highly atypical, annular fashion. A review of systems was otherwise negative, and CT ruled out osteoarticular involvement.

In addition to socioeconomic barriers, several factors contributed to a delayed diagnosis in this patient including the annular presentation with central hypopigmentation and atrophy, negative initial microbiological cultures and lack of visualization of organisms on histopathology, and the consequent need for repeat biopsies. For lymphocutaneous sporotrichosis, the typical presentation consists of a papule or ulcerated nodule at the site of inoculation with subsequent linear spread along lymphatic channels. This classic sporotrichoid pattern is a key diagnostic clue for identifying sporotrichosis but was absent at the time our patient presented for medical care. Rather, the sporotrichoid spread seemed to have occurred in a centrifugal fashion up the leg. Few case reports have documented an annular presentation of lymphocutaneous sporotrichosis,^8-13 and one report described central atrophy and hypopigmentation.¹⁰ Pain and pruritus, which were present in our patient, rarely are documented.⁹ Finally, the diagnosis of cutaneous fungal infections may require multiple biopsies due to the variable abundance of viable organisms in tissue specimens as well as the fastidious growth characteristics of these organisms. Furthermore, sensitivity often is low for both fungal and mycobacterial cultures, and cultures may take days to weeks to yield growth.^14,15 For these reasons, empiric therapy and repeat biopsies often are pursued if clinical suspicion is high enough.¹⁶ Our patient returned for multiple scouting biopsies after the initial tissue culture was negative and was even considered for empiric treatment against Mycobacterium prior to positive fungal cultures.

Another unique aspect of our case was the presence of a keloid. It is difficult to know if this keloid was secondary to the trauma the patient sustained in the inciting incident or formed from the fungal infection. Interestingly, it has been hypothesized that fungal infections may contribute to keloid and hypertrophic scar formation.¹⁷ In a case series of 3 patients with either keloids or hypertrophic scars and concomitant tinea infection, there was notable improvement in the appearance of the scars 2 weeks after beginning itraconazole therapy.¹⁷ However, it is not yet known if a fungal infection can contribute to the pathogenesis of keloid formation.

As with other aspects of this case, the length of time the patient went without diagnosis and treatment was unusual and may help explain the atypical presentation. Although the incubation period for S schenckii can vary, most reports identify patients as seeking medical attention within 1 year of rash onset.^18-20 In our case, the patient was not diagnosed until 8 years after his symptoms began, requiring multiple referrals, multiple health system touchpoints, and an institution-specific financial aid program. As such, this case also highlights the potential need for a multidisciplinary team approach when caring for patients with poor access to health care.

In conclusion, this case illustrates a unique presentation of lymphocutaneous sporotrichosis that may mimic other chronic infections and result in delayed diagnosis. Although lymphangitic sporotrichosis generally is recognized as having a linear distribution, mounting evidence from this report and others suggests an annular presentation also is possible. Pruritus or pain is rare but should not preclude a diagnosis of sporotrichosis if present. For patients with limited access to health care resources, it is especially important to involve multiple members of the health care team, including social workers and specialists, to prevent a protracted and severe course of disease.

To the Editor:

Cases of primary varicella-zoster virus (VZV) are relatively uncommon in the United States since the introduction of the varicella vaccine in 1995, with an overall decline in cases of more than 97%.¹ Prior to the vaccine, 70% of hospitalizations occurred in children; subsequently, hospitalizations among the pediatric population (aged ≤20 years) declined by 97%. Compared to children, adults and immunocompromised patients with VZV infection may present with more severe disease and experience more complications.¹

Most children in the United States are vaccinated against VZV, with 90.3% receiving at least 1 dose by 24 months of age.² However, many countries do not implement universal varicella vaccination for infants.³ As a result, physicians should remember to include primary varicella in the differential when clinically correlated, especially when evaluating patients who have immigrated to the United States or who may be living in unvaccinated communities. We report 2 cases of primary VZV manifesting in adults to remind readers of the salient clinical features of this disease and how dermatologists play a critical role in early and accurate identification of diseases that can have wide-reaching public health implications.

A 26-year-old man with no relevant medical history presented to the emergency department with an itchy and painful rash of 5 days’ duration that began on the trunk and spread to the face, lips, feet, hands, arms, and legs. He also reported shortness of breath, cough, and chills, and he had a temperature of 100.8 °F (38.2 °C). Physical examination revealed numerous erythematous papules and vesiculopustules, some with central umbilication and some with overlying gold crusts (Figure 1).

Later that day, a 47-year-old man with no relevant medical history presented to the same emergency department with a rash along with self-reported fever and sore throat of 3 days’ duration. Physical examination found innumerable erythematous vesicopustules scattered on the face, scalp, neck, trunk, arms, and legs, some with a “dew drop on a rose petal” appearance and some with overlying hemorrhagic crust (Figure 2).

Although infection was of primary concern for the first patient, the presentation of the second patient prompted specific concern for primary VZV infection in both patients, who were placed on airborne and contact isolation precautions.

Skin biopsies from both patients showed acantholytic blisters, hair follicle necrosis, and marked dermal inflammation (Figure 3). Herpetic viral changes were seen in keratinocytes, with steel-grey nuclei, multinucleated keratinocytes, and chromatin margination. An immunostain for VZV was diffusely positive, and VZV antibody IgG was positive (Figure 4).

Upon additional questioning, both patients reported recent exposure to VZV-like illnesses in family members without a history of international travel. Neither of the patients was sure of their vaccination status or prior infection history. Both patients received intravenous acyclovir 10 mg/kg administered every 8 hours. Both patients experienced improvement and were discharged after 3 days on oral valacyclovir (1 g 3 times daily for a 7-day treatment course).

The similar presentation and timing of these 2 VZV cases caused concern for an unidentified community outbreak. The infection control team was notified; additionally, per hospital protocol the state health department was alerted as well as the clinicians and staff of the hospital with a request to be vigilant for further cases.

Despite high vaccination rates in the United States, outbreaks of varicella still occur, particularly among unvaccinated individuals, and a robust and efficient response is necessary to control the spread of such outbreaks.⁴ Many states, including Arkansas where our cases occurred, have laws mandating report of VZV cases to the department of health.⁵ Dermatologists play an important role in reporting cases, aiding in diagnosis through recognition of the physical examination findings, obtaining appropriate biopsy, and recommending additional laboratory testing.

Typical skin manifestations include a pruritic rash of macules, papules, vesicles, and crusted lesions distributed throughout the trunk, face, arms, and legs. Because new lesions appear over several days, they will be in different stages of healing, resulting in the simultaneous presence of papules, vesicles, and crusted lesions.⁶ This unique characteristic helps distinguish VZV from other skin diseases such as smallpox or mpox (monkeypox), which generally show lesions in similar stages of evolution.

Biopsy also can aid in identification. Viruses in the herpes family reveal similar histopathologic characteristics, including acantholysis and vesicle formation, intranuclear inclusions with margination of chromatin, multinucleation, and nuclear molding.⁷ Immunohistochemistry can be used to differentiate VZV from herpes simplex virus; however, neither microscopic examination nor immunohistochemistry distinguish primary VZV infection from herpes zoster (HZ).⁸

The mpox rash progresses more slowly than a VZV rash and has a centrifugal rather than central distribution that can involve the palms and soles. Lymphadenopathy is a characteristic finding in mpox.⁹ Rickettsialpox is distinguished from VZV primarily by the appearance of brown or black eschar after the original papulovesicular lesions dry out.¹⁰ Atypical hand, foot, and mouth disease can manifest in adults as widespread papulovesicular lesions. This form is associated with coxsackievirus A6 and may require direct fluorescent antibody assay or polymerase chain reaction of keratinocytes to rule out VZV.¹¹

Herpes zoster occurs in older adults with a history of primary VZV.⁶ It manifests as vesicular lesions confined to 1 or 2 adjacent dermatomes vs the diffuse spread of VZV over the entire body. However, HZ can become disseminated in immunocompromised individuals, making it difficult to clinically distinguish from VZV.⁶ Serology can be helpful, as high IgM titers indicate an acute primary VZV infection. Subsequently increased IgG titers steadily wane over time and spike during reactivation.¹²

Dermatology and infectious disease consultations in our cases yielded a preliminary diagnosis through physical examination that was confirmed by biopsy and subsequent laboratory testing, which allowed for a swift response by the infection control team including isolation precautions to control a potential outbreak. Patients with VZV should remain in respiratory isolation until all lesions have crusted over.⁶

Individuals who had face-to-face indoor contact for at least 5 minutes or who shared a living space with an infected individual should be assessed for VZV immunity, which is defined as confirmed prior immunization or infection.^5,13 Lack of VZV immunity requires postexposure prophylaxis—active immunization for the immunocompetent and passive immunization for the immunocompromised.¹³ Ultimately, no additional cases were reported in the community where our patients resided.

Immunocompetent children with primary VZV require supportive care only. Oral antiviral therapy is the treatment of choice for immunocompetent adults or anyone at increased risk for complications, while intravenous antivirals are recommended for the immunocompromised or those with VZV-related complications.¹⁴ A similar approach is used for HZ. Uncomplicated cases are treated with oral antivirals, and complicated cases (eg, HZ ophthalmicus) are treated with intravenous antivirals.¹⁵ Commonly used antivirals include acyclovir, valacyclovir, and famciclovir.¹⁴

Our cases highlight the ongoing risk for varicella outbreaks in unvaccinated or undervaccinated communities. Physician vigilance is necessary, and dermatology plays a particularly important role in swift and accurate detection of VZV, as demonstrated in our cases by the recognition of classic physical examination findings of erythematous and vesicular papules in each of the patients. Because primary VZV infection can result in life-threatening complications including hepatitis, encephalitis, and pancreatitis, prompt identification and initiation of therapy is important.⁶ Similarly, quick notification of public health officials about detected primary VZV cases is vital to containing potential community outbreaks.

To the Editor:

Cases of primary varicella-zoster virus (VZV) are relatively uncommon in the United States since the introduction of the varicella vaccine in 1995, with an overall decline in cases of more than 97%.¹ Prior to the vaccine, 70% of hospitalizations occurred in children; subsequently, hospitalizations among the pediatric population (aged ≤20 years) declined by 97%. Compared to children, adults and immunocompromised patients with VZV infection may present with more severe disease and experience more complications.¹

Most children in the United States are vaccinated against VZV, with 90.3% receiving at least 1 dose by 24 months of age.² However, many countries do not implement universal varicella vaccination for infants.³ As a result, physicians should remember to include primary varicella in the differential when clinically correlated, especially when evaluating patients who have immigrated to the United States or who may be living in unvaccinated communities. We report 2 cases of primary VZV manifesting in adults to remind readers of the salient clinical features of this disease and how dermatologists play a critical role in early and accurate identification of diseases that can have wide-reaching public health implications.

A 26-year-old man with no relevant medical history presented to the emergency department with an itchy and painful rash of 5 days’ duration that began on the trunk and spread to the face, lips, feet, hands, arms, and legs. He also reported shortness of breath, cough, and chills, and he had a temperature of 100.8 °F (38.2 °C). Physical examination revealed numerous erythematous papules and vesiculopustules, some with central umbilication and some with overlying gold crusts (Figure 1).

Later that day, a 47-year-old man with no relevant medical history presented to the same emergency department with a rash along with self-reported fever and sore throat of 3 days’ duration. Physical examination found innumerable erythematous vesicopustules scattered on the face, scalp, neck, trunk, arms, and legs, some with a “dew drop on a rose petal” appearance and some with overlying hemorrhagic crust (Figure 2).

Although infection was of primary concern for the first patient, the presentation of the second patient prompted specific concern for primary VZV infection in both patients, who were placed on airborne and contact isolation precautions.

Skin biopsies from both patients showed acantholytic blisters, hair follicle necrosis, and marked dermal inflammation (Figure 3). Herpetic viral changes were seen in keratinocytes, with steel-grey nuclei, multinucleated keratinocytes, and chromatin margination. An immunostain for VZV was diffusely positive, and VZV antibody IgG was positive (Figure 4).

Upon additional questioning, both patients reported recent exposure to VZV-like illnesses in family members without a history of international travel. Neither of the patients was sure of their vaccination status or prior infection history. Both patients received intravenous acyclovir 10 mg/kg administered every 8 hours. Both patients experienced improvement and were discharged after 3 days on oral valacyclovir (1 g 3 times daily for a 7-day treatment course).

The similar presentation and timing of these 2 VZV cases caused concern for an unidentified community outbreak. The infection control team was notified; additionally, per hospital protocol the state health department was alerted as well as the clinicians and staff of the hospital with a request to be vigilant for further cases.

Despite high vaccination rates in the United States, outbreaks of varicella still occur, particularly among unvaccinated individuals, and a robust and efficient response is necessary to control the spread of such outbreaks.⁴ Many states, including Arkansas where our cases occurred, have laws mandating report of VZV cases to the department of health.⁵ Dermatologists play an important role in reporting cases, aiding in diagnosis through recognition of the physical examination findings, obtaining appropriate biopsy, and recommending additional laboratory testing.

Typical skin manifestations include a pruritic rash of macules, papules, vesicles, and crusted lesions distributed throughout the trunk, face, arms, and legs. Because new lesions appear over several days, they will be in different stages of healing, resulting in the simultaneous presence of papules, vesicles, and crusted lesions.⁶ This unique characteristic helps distinguish VZV from other skin diseases such as smallpox or mpox (monkeypox), which generally show lesions in similar stages of evolution.

Biopsy also can aid in identification. Viruses in the herpes family reveal similar histopathologic characteristics, including acantholysis and vesicle formation, intranuclear inclusions with margination of chromatin, multinucleation, and nuclear molding.⁷ Immunohistochemistry can be used to differentiate VZV from herpes simplex virus; however, neither microscopic examination nor immunohistochemistry distinguish primary VZV infection from herpes zoster (HZ).⁸

The mpox rash progresses more slowly than a VZV rash and has a centrifugal rather than central distribution that can involve the palms and soles. Lymphadenopathy is a characteristic finding in mpox.⁹ Rickettsialpox is distinguished from VZV primarily by the appearance of brown or black eschar after the original papulovesicular lesions dry out.¹⁰ Atypical hand, foot, and mouth disease can manifest in adults as widespread papulovesicular lesions. This form is associated with coxsackievirus A6 and may require direct fluorescent antibody assay or polymerase chain reaction of keratinocytes to rule out VZV.¹¹

Herpes zoster occurs in older adults with a history of primary VZV.⁶ It manifests as vesicular lesions confined to 1 or 2 adjacent dermatomes vs the diffuse spread of VZV over the entire body. However, HZ can become disseminated in immunocompromised individuals, making it difficult to clinically distinguish from VZV.⁶ Serology can be helpful, as high IgM titers indicate an acute primary VZV infection. Subsequently increased IgG titers steadily wane over time and spike during reactivation.¹²

Dermatology and infectious disease consultations in our cases yielded a preliminary diagnosis through physical examination that was confirmed by biopsy and subsequent laboratory testing, which allowed for a swift response by the infection control team including isolation precautions to control a potential outbreak. Patients with VZV should remain in respiratory isolation until all lesions have crusted over.⁶

Individuals who had face-to-face indoor contact for at least 5 minutes or who shared a living space with an infected individual should be assessed for VZV immunity, which is defined as confirmed prior immunization or infection.^5,13 Lack of VZV immunity requires postexposure prophylaxis—active immunization for the immunocompetent and passive immunization for the immunocompromised.¹³ Ultimately, no additional cases were reported in the community where our patients resided.

Immunocompetent children with primary VZV require supportive care only. Oral antiviral therapy is the treatment of choice for immunocompetent adults or anyone at increased risk for complications, while intravenous antivirals are recommended for the immunocompromised or those with VZV-related complications.¹⁴ A similar approach is used for HZ. Uncomplicated cases are treated with oral antivirals, and complicated cases (eg, HZ ophthalmicus) are treated with intravenous antivirals.¹⁵ Commonly used antivirals include acyclovir, valacyclovir, and famciclovir.¹⁴

Our cases highlight the ongoing risk for varicella outbreaks in unvaccinated or undervaccinated communities. Physician vigilance is necessary, and dermatology plays a particularly important role in swift and accurate detection of VZV, as demonstrated in our cases by the recognition of classic physical examination findings of erythematous and vesicular papules in each of the patients. Because primary VZV infection can result in life-threatening complications including hepatitis, encephalitis, and pancreatitis, prompt identification and initiation of therapy is important.⁶ Similarly, quick notification of public health officials about detected primary VZV cases is vital to containing potential community outbreaks.

To the Editor:

Cases of primary varicella-zoster virus (VZV) are relatively uncommon in the United States since the introduction of the varicella vaccine in 1995, with an overall decline in cases of more than 97%.¹ Prior to the vaccine, 70% of hospitalizations occurred in children; subsequently, hospitalizations among the pediatric population (aged ≤20 years) declined by 97%. Compared to children, adults and immunocompromised patients with VZV infection may present with more severe disease and experience more complications.¹

Most children in the United States are vaccinated against VZV, with 90.3% receiving at least 1 dose by 24 months of age.² However, many countries do not implement universal varicella vaccination for infants.³ As a result, physicians should remember to include primary varicella in the differential when clinically correlated, especially when evaluating patients who have immigrated to the United States or who may be living in unvaccinated communities. We report 2 cases of primary VZV manifesting in adults to remind readers of the salient clinical features of this disease and how dermatologists play a critical role in early and accurate identification of diseases that can have wide-reaching public health implications.

A 26-year-old man with no relevant medical history presented to the emergency department with an itchy and painful rash of 5 days’ duration that began on the trunk and spread to the face, lips, feet, hands, arms, and legs. He also reported shortness of breath, cough, and chills, and he had a temperature of 100.8 °F (38.2 °C). Physical examination revealed numerous erythematous papules and vesiculopustules, some with central umbilication and some with overlying gold crusts (Figure 1).

Later that day, a 47-year-old man with no relevant medical history presented to the same emergency department with a rash along with self-reported fever and sore throat of 3 days’ duration. Physical examination found innumerable erythematous vesicopustules scattered on the face, scalp, neck, trunk, arms, and legs, some with a “dew drop on a rose petal” appearance and some with overlying hemorrhagic crust (Figure 2).

Although infection was of primary concern for the first patient, the presentation of the second patient prompted specific concern for primary VZV infection in both patients, who were placed on airborne and contact isolation precautions.

Skin biopsies from both patients showed acantholytic blisters, hair follicle necrosis, and marked dermal inflammation (Figure 3). Herpetic viral changes were seen in keratinocytes, with steel-grey nuclei, multinucleated keratinocytes, and chromatin margination. An immunostain for VZV was diffusely positive, and VZV antibody IgG was positive (Figure 4).

Upon additional questioning, both patients reported recent exposure to VZV-like illnesses in family members without a history of international travel. Neither of the patients was sure of their vaccination status or prior infection history. Both patients received intravenous acyclovir 10 mg/kg administered every 8 hours. Both patients experienced improvement and were discharged after 3 days on oral valacyclovir (1 g 3 times daily for a 7-day treatment course).

The similar presentation and timing of these 2 VZV cases caused concern for an unidentified community outbreak. The infection control team was notified; additionally, per hospital protocol the state health department was alerted as well as the clinicians and staff of the hospital with a request to be vigilant for further cases.

Despite high vaccination rates in the United States, outbreaks of varicella still occur, particularly among unvaccinated individuals, and a robust and efficient response is necessary to control the spread of such outbreaks.⁴ Many states, including Arkansas where our cases occurred, have laws mandating report of VZV cases to the department of health.⁵ Dermatologists play an important role in reporting cases, aiding in diagnosis through recognition of the physical examination findings, obtaining appropriate biopsy, and recommending additional laboratory testing.

Typical skin manifestations include a pruritic rash of macules, papules, vesicles, and crusted lesions distributed throughout the trunk, face, arms, and legs. Because new lesions appear over several days, they will be in different stages of healing, resulting in the simultaneous presence of papules, vesicles, and crusted lesions.⁶ This unique characteristic helps distinguish VZV from other skin diseases such as smallpox or mpox (monkeypox), which generally show lesions in similar stages of evolution.

Biopsy also can aid in identification. Viruses in the herpes family reveal similar histopathologic characteristics, including acantholysis and vesicle formation, intranuclear inclusions with margination of chromatin, multinucleation, and nuclear molding.⁷ Immunohistochemistry can be used to differentiate VZV from herpes simplex virus; however, neither microscopic examination nor immunohistochemistry distinguish primary VZV infection from herpes zoster (HZ).⁸

The mpox rash progresses more slowly than a VZV rash and has a centrifugal rather than central distribution that can involve the palms and soles. Lymphadenopathy is a characteristic finding in mpox.⁹ Rickettsialpox is distinguished from VZV primarily by the appearance of brown or black eschar after the original papulovesicular lesions dry out.¹⁰ Atypical hand, foot, and mouth disease can manifest in adults as widespread papulovesicular lesions. This form is associated with coxsackievirus A6 and may require direct fluorescent antibody assay or polymerase chain reaction of keratinocytes to rule out VZV.¹¹

Herpes zoster occurs in older adults with a history of primary VZV.⁶ It manifests as vesicular lesions confined to 1 or 2 adjacent dermatomes vs the diffuse spread of VZV over the entire body. However, HZ can become disseminated in immunocompromised individuals, making it difficult to clinically distinguish from VZV.⁶ Serology can be helpful, as high IgM titers indicate an acute primary VZV infection. Subsequently increased IgG titers steadily wane over time and spike during reactivation.¹²

Dermatology and infectious disease consultations in our cases yielded a preliminary diagnosis through physical examination that was confirmed by biopsy and subsequent laboratory testing, which allowed for a swift response by the infection control team including isolation precautions to control a potential outbreak. Patients with VZV should remain in respiratory isolation until all lesions have crusted over.⁶

Individuals who had face-to-face indoor contact for at least 5 minutes or who shared a living space with an infected individual should be assessed for VZV immunity, which is defined as confirmed prior immunization or infection.^5,13 Lack of VZV immunity requires postexposure prophylaxis—active immunization for the immunocompetent and passive immunization for the immunocompromised.¹³ Ultimately, no additional cases were reported in the community where our patients resided.

Immunocompetent children with primary VZV require supportive care only. Oral antiviral therapy is the treatment of choice for immunocompetent adults or anyone at increased risk for complications, while intravenous antivirals are recommended for the immunocompromised or those with VZV-related complications.¹⁴ A similar approach is used for HZ. Uncomplicated cases are treated with oral antivirals, and complicated cases (eg, HZ ophthalmicus) are treated with intravenous antivirals.¹⁵ Commonly used antivirals include acyclovir, valacyclovir, and famciclovir.¹⁴

Our cases highlight the ongoing risk for varicella outbreaks in unvaccinated or undervaccinated communities. Physician vigilance is necessary, and dermatology plays a particularly important role in swift and accurate detection of VZV, as demonstrated in our cases by the recognition of classic physical examination findings of erythematous and vesicular papules in each of the patients. Because primary VZV infection can result in life-threatening complications including hepatitis, encephalitis, and pancreatitis, prompt identification and initiation of therapy is important.⁶ Similarly, quick notification of public health officials about detected primary VZV cases is vital to containing potential community outbreaks.

A retrospective analysis of Medicare data revealed that between 2000 and 2017, immunohistochemistry (IHC) claims associated with melanoma diagnoses grew from 11% to 51%. Rising utilization — and substantial geographic variation in practice patterns — argue for further research to optimize IHC use in the diagnoses of melanoma, according to the authors.

But with sparse guidance regarding best practices for IHC in melanoma diagnosis, concerns for appropriate use are rising, they wrote in their report, recently published in JAMA Dermatology.

Kenechukwu Ojukwu, MD, MPP, of the department of pathology and laboratory medicine, University of California, Los Angeles, and coinvestigators, searched the Surveillance, Epidemiology, and End Results (SEER)–Medicare database for incident in situ or invasive cutaneous melanoma in patients 65 years and older and accompanying IHC claims made during the month of diagnosis through 14 days afterward.

Among 132,547 melanomas in 116,117 patients, 43,396 (33%) had accompanying IHC claims. Such claims were less common with increasing age, declining from 44% in patients aged 65-74 years to 18% in patients 85 aged years and older. Although melanoma incidence increased throughout the period studied, melanoma mortality rates remained relatively stable.

By summary stage at diagnosis, IHC utilization ranged from 29% of in situ cases to 75% of distant cases. After the researchers controlled for year of diagnosis, IHC use was statistically significantly associated with all demographic, tumor, and geographic characteristics examined, except race and ethnicity. Across all the years of the study, regional usage ranged from a low of 22% in Detroit to a high of 44% in both Louisiana and San Jose-Monterey, California. Figures for 2017 ranged from 39% of cases in Kentucky and Atlanta to 68% in New Mexico.

“Given the extensive use of IHC in clinical practice,” the authors concluded, “studies examining the resulting outcomes of IHC on different domains, such as symptom burden, quality of life, and mortality, are crucial.”

The “notable” regional variation in IHC utilization suggests uncertainty about its optimal employment in clinical practice, and, they wrote, “these findings highlight the need for research to identify where IHC provides the most value and to develop guidelines regarding the appropriate use of IHC.”

In an accompanying JAMA Dermatology editorial, Alexandra Flamm, MD, wrote, “now is an exciting time to practice dermatopathology, with an increased number of ancillary tests, such as IHC, that can be used to diagnose malignant neoplasms more precisely and to more accurately determine prognosis and therapeutic options in this age of precision medicine”.

However, added Dr. Flamm, a dermatologist and dermatopathologist at New York University, New York City, the increasing number of ancillary tests is fueling awareness of appropriate use and the importance of ensuring high-quality, value-based healthcare. “With this increased scrutiny on the appropriateness of ancillary histopathologic testing within dermatopathology,” she wrote, “the need is growing for parameters that can be used to guide when to use IHC testing and other ancillary testing.” And using dermatopathologist-developed tools such as American Society of Dermatopathology guidelines for 11 IHC tests can help ensure that appropriate medical decision-making is taken into account when creating these tools, she added.

IHC Usage Growing

“The paper confirms what I already knew,” said Whitney High, MD, JD, who was not involved with the study and was asked to comment on the results. “Use of IHC in dermatopathology has increased substantially, and probably will continue to increase over time.” The societal burden of IHC costs represents a legitimate concern, said Dr. High, professor of dermatology and pathology and director of dermatopathology at the University of Colorado, Aurora.

“However,” he told this news organization, “the histologic diagnosis of melanoma is sometimes substantially subjective — and all physicians, including pathologists, even though they are not providing care in the physical presence of the patient, are fiduciaries.” If an IHC stain would meaningfully improve a patient’s care, he said, physicians should attempt to provide it, unless strictly disallowed by a payer. Controlling medical-care costs might be better left to professional societies to guide care standards over time, he noted.

Dr. High

A retrospective analysis of Medicare data revealed that between 2000 and 2017, immunohistochemistry (IHC) claims associated with melanoma diagnoses grew from 11% to 51%. Rising utilization — and substantial geographic variation in practice patterns — argue for further research to optimize IHC use in the diagnoses of melanoma, according to the authors.

But with sparse guidance regarding best practices for IHC in melanoma diagnosis, concerns for appropriate use are rising, they wrote in their report, recently published in JAMA Dermatology.

Kenechukwu Ojukwu, MD, MPP, of the department of pathology and laboratory medicine, University of California, Los Angeles, and coinvestigators, searched the Surveillance, Epidemiology, and End Results (SEER)–Medicare database for incident in situ or invasive cutaneous melanoma in patients 65 years and older and accompanying IHC claims made during the month of diagnosis through 14 days afterward.

Among 132,547 melanomas in 116,117 patients, 43,396 (33%) had accompanying IHC claims. Such claims were less common with increasing age, declining from 44% in patients aged 65-74 years to 18% in patients 85 aged years and older. Although melanoma incidence increased throughout the period studied, melanoma mortality rates remained relatively stable.

By summary stage at diagnosis, IHC utilization ranged from 29% of in situ cases to 75% of distant cases. After the researchers controlled for year of diagnosis, IHC use was statistically significantly associated with all demographic, tumor, and geographic characteristics examined, except race and ethnicity. Across all the years of the study, regional usage ranged from a low of 22% in Detroit to a high of 44% in both Louisiana and San Jose-Monterey, California. Figures for 2017 ranged from 39% of cases in Kentucky and Atlanta to 68% in New Mexico.

“Given the extensive use of IHC in clinical practice,” the authors concluded, “studies examining the resulting outcomes of IHC on different domains, such as symptom burden, quality of life, and mortality, are crucial.”

The “notable” regional variation in IHC utilization suggests uncertainty about its optimal employment in clinical practice, and, they wrote, “these findings highlight the need for research to identify where IHC provides the most value and to develop guidelines regarding the appropriate use of IHC.”

In an accompanying JAMA Dermatology editorial, Alexandra Flamm, MD, wrote, “now is an exciting time to practice dermatopathology, with an increased number of ancillary tests, such as IHC, that can be used to diagnose malignant neoplasms more precisely and to more accurately determine prognosis and therapeutic options in this age of precision medicine”.

However, added Dr. Flamm, a dermatologist and dermatopathologist at New York University, New York City, the increasing number of ancillary tests is fueling awareness of appropriate use and the importance of ensuring high-quality, value-based healthcare. “With this increased scrutiny on the appropriateness of ancillary histopathologic testing within dermatopathology,” she wrote, “the need is growing for parameters that can be used to guide when to use IHC testing and other ancillary testing.” And using dermatopathologist-developed tools such as American Society of Dermatopathology guidelines for 11 IHC tests can help ensure that appropriate medical decision-making is taken into account when creating these tools, she added.

IHC Usage Growing

“The paper confirms what I already knew,” said Whitney High, MD, JD, who was not involved with the study and was asked to comment on the results. “Use of IHC in dermatopathology has increased substantially, and probably will continue to increase over time.” The societal burden of IHC costs represents a legitimate concern, said Dr. High, professor of dermatology and pathology and director of dermatopathology at the University of Colorado, Aurora.

“However,” he told this news organization, “the histologic diagnosis of melanoma is sometimes substantially subjective — and all physicians, including pathologists, even though they are not providing care in the physical presence of the patient, are fiduciaries.” If an IHC stain would meaningfully improve a patient’s care, he said, physicians should attempt to provide it, unless strictly disallowed by a payer. Controlling medical-care costs might be better left to professional societies to guide care standards over time, he noted.

Dr. High

A retrospective analysis of Medicare data revealed that between 2000 and 2017, immunohistochemistry (IHC) claims associated with melanoma diagnoses grew from 11% to 51%. Rising utilization — and substantial geographic variation in practice patterns — argue for further research to optimize IHC use in the diagnoses of melanoma, according to the authors.

But with sparse guidance regarding best practices for IHC in melanoma diagnosis, concerns for appropriate use are rising, they wrote in their report, recently published in JAMA Dermatology.

Kenechukwu Ojukwu, MD, MPP, of the department of pathology and laboratory medicine, University of California, Los Angeles, and coinvestigators, searched the Surveillance, Epidemiology, and End Results (SEER)–Medicare database for incident in situ or invasive cutaneous melanoma in patients 65 years and older and accompanying IHC claims made during the month of diagnosis through 14 days afterward.

Among 132,547 melanomas in 116,117 patients, 43,396 (33%) had accompanying IHC claims. Such claims were less common with increasing age, declining from 44% in patients aged 65-74 years to 18% in patients 85 aged years and older. Although melanoma incidence increased throughout the period studied, melanoma mortality rates remained relatively stable.

By summary stage at diagnosis, IHC utilization ranged from 29% of in situ cases to 75% of distant cases. After the researchers controlled for year of diagnosis, IHC use was statistically significantly associated with all demographic, tumor, and geographic characteristics examined, except race and ethnicity. Across all the years of the study, regional usage ranged from a low of 22% in Detroit to a high of 44% in both Louisiana and San Jose-Monterey, California. Figures for 2017 ranged from 39% of cases in Kentucky and Atlanta to 68% in New Mexico.

“Given the extensive use of IHC in clinical practice,” the authors concluded, “studies examining the resulting outcomes of IHC on different domains, such as symptom burden, quality of life, and mortality, are crucial.”

The “notable” regional variation in IHC utilization suggests uncertainty about its optimal employment in clinical practice, and, they wrote, “these findings highlight the need for research to identify where IHC provides the most value and to develop guidelines regarding the appropriate use of IHC.”

In an accompanying JAMA Dermatology editorial, Alexandra Flamm, MD, wrote, “now is an exciting time to practice dermatopathology, with an increased number of ancillary tests, such as IHC, that can be used to diagnose malignant neoplasms more precisely and to more accurately determine prognosis and therapeutic options in this age of precision medicine”.

However, added Dr. Flamm, a dermatologist and dermatopathologist at New York University, New York City, the increasing number of ancillary tests is fueling awareness of appropriate use and the importance of ensuring high-quality, value-based healthcare. “With this increased scrutiny on the appropriateness of ancillary histopathologic testing within dermatopathology,” she wrote, “the need is growing for parameters that can be used to guide when to use IHC testing and other ancillary testing.” And using dermatopathologist-developed tools such as American Society of Dermatopathology guidelines for 11 IHC tests can help ensure that appropriate medical decision-making is taken into account when creating these tools, she added.

IHC Usage Growing

“The paper confirms what I already knew,” said Whitney High, MD, JD, who was not involved with the study and was asked to comment on the results. “Use of IHC in dermatopathology has increased substantially, and probably will continue to increase over time.” The societal burden of IHC costs represents a legitimate concern, said Dr. High, professor of dermatology and pathology and director of dermatopathology at the University of Colorado, Aurora.

“However,” he told this news organization, “the histologic diagnosis of melanoma is sometimes substantially subjective — and all physicians, including pathologists, even though they are not providing care in the physical presence of the patient, are fiduciaries.” If an IHC stain would meaningfully improve a patient’s care, he said, physicians should attempt to provide it, unless strictly disallowed by a payer. Controlling medical-care costs might be better left to professional societies to guide care standards over time, he noted.

Dr. High

The Diagnosis: Blastic Plasmacytoid Dendritic Cell Neoplasm

Cutaneous plasmacytoma initially was suspected because of the patient’s history of monoclonal gammopathy as well as angiosarcoma due to the purpuric vascular appearance of the lesions. However, histopathology revealed a pleomorphic cellular dermal infiltrate characterized by atypical cells with mediumlarge nuclei, fine chromatin, and small nucleoli; the cells also had little cytoplasm (Figure). The infiltrate did not involve the epidermis but extended into the subcutaneous tissue. Immunohistochemistry revealed that the cells were positive for CD45, CD43, CD4, CD7, CD56, CD123, CD33, T-cell leukemia/lymphoma protein 1, and CD68. The cells were negative for CD2, CD3, CD5, CD8, T-cell intracellular antigen 1, CD13, CD15, CD19, CD20, CD21, CD23, cyclin D1, Bcl-2, Bcl-6, CD10, PAX5, MUM1, lysozyme, myeloperoxidase, perforin, granzyme B, CD57, CD34, CD117, terminal deoxynucleotidyl transferase, activin receptorlike kinase 1 βF1, Epstein-Barr virus– encoded small RNA, CD30, CD163, and pancytokeratin. Thus, the clinical and histopathologic findings led to a diagnosis of blastic plasmacytoid dendritic cell neoplasm (BPDCN), a rare and aggressive hematologic malignancy.

Blastic plasmacytoid dendritic cell neoplasm affects males older than 60 years.¹ It is characterized by the clonal proliferation of precursor plasmacytoid dendritic cells—otherwise known as professional type I interferonproducing cells or plasmacytoid monocytes—of myeloid origin. Plasmacytoid dendritic cells have been renamed on several occasions, reflecting uncertainties of their histogenesis. The diagnosis of BPDCN requires a biopsy showing the morphology of plasmacytoid dendritic blast cells and immunophenotypic criteria established by either immunohistochemistry or flow cytometry.^2,3 Tumor cells morphologically show an immature blastic appearance, and the diagnosis rests upon the demonstration of CD4 and CD56, together with markers more restricted to plasmacytoid dendritic cells (eg, BDCA-2, CD123, T-cell leukemia/lymphoma protein 1, CD2AP, BCL11A) and negativity for lymphoid and myeloid lineage–associated antigens.^1,4

Blastic plasmacytoid dendritic cell neoplasms account for less than 1% of all hematopoietic neoplasms. Cutaneous lesions occur in 64% of patients with the disease and often are the reason patients seek medical care.⁵ Clinical findings include numerous erythematous and violaceous papules, nodules, and plaques that resemble purpura or vasculitis. Cutaneous lesions can vary in size from a few millimeters to 10 cm and vary in color. Moreover, patients often present with bruiselike patches, disseminated lesions, or mucosal lesions.¹ Extracutaneous involvement includes lymphadenopathy, splenomegaly, and cytopenia caused by bone marrow infiltration, which may be present at diagnosis or during disease progression. Bone marrow involvement often is present with thrombocytopenia, anemia, and neutropenia. One-third of patients with BPDCN have central nervous system involvement and no disease relapse.⁶ Other affected sites include the liver, lungs, tonsils, soft tissues, and eyes. Patients with BPDCN may present with a history of myeloid neoplasms, such as acute/chronic myeloid leukemia, chronic myelomonocytic leukemia, or myelodysplastic syndrome.⁴ Our case highlights the importance of skin biopsy for making the correct diagnosis, as BPDCN manifests with cutaneous lesions that are nonspecific for neoplastic or nonneoplastic etiologies.

Given the aggressive nature of BPDCN, along with its potential for acute leukemic transformation, treatment has been challenging due to both poor response rates and lack of consensus and treatment strategies. Historically, patients who have received high-dose acute leukemia–based chemotherapy followed by an allogeneic stem cell transplant during the first remission appeared to have the best outcomes.⁷ Conventional treatments have included surgical excision with radiation and various leukemia-based chemotherapy regimens, with hyper- CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone-methotrexate, and cytarabine) being the most commonly used regimen.^7,8 Venetoclax, a B-cell lymphoma 2 protein inhibitor, has shown promise when used in combination with hyper-CVAD. For older patients who may not tolerate aggressive chemotherapy, hypomethylating agents are preferred for their tolerability. Although tagraxofusp, a CD123-directed cytotoxin, has been utilized, Sapienza et al⁹ demonstrated an association with capillary leak syndrome.

Leukemia cutis is characterized by infiltration of the skin by malignant leukocytes, often associated with a prior diagnosis of systemic leukemia or myelodysplasia. Extramedullary accumulation of leukemic cells typically is referred to as myeloid sarcoma, while leukemia cutis serves as a general term for specific skin involvement.¹⁰ In rare instances, cutaneous lesions may manifest as the initial sign of systemic disease.

Cutaneous T-cell lymphomas comprise a diverse group of non-Hodgkin lymphomas that manifest as malignant monoclonal T-lymphocyte infiltration in the skin. Mycosis fungoides, Sézary syndrome, and primary cutaneous peripheral T-cell lymphomas are among the key subtypes. Histologically, differentiating these conditions from benign inflammatory disorders can be challenging due to subtle features such as haloed lymphocytes, epidermotropism, and Pautrier microabscesses seen in mycosis fungoides.¹¹

Multiple myeloma involves monoclonal plasma cell proliferation, primarily affecting bone and bone marrow. Extramedullary plasmacytomas can occur outside these sites through hematogenous spread or adjacent infiltration, while metastatic plasmacytomas result from metastasis. Cutaneous plasmacytomas may arise from hematogenous dissemination or infiltration from neighboring structures.¹²

Extranodal natural killer/T-cell lymphoma, nasal type, manifests as aggressive mid-facial necrotizing lesions with extranodal involvement, notably in the nasal/paranasal area. These lesions can cause local destruction of cartilage, bone, and soft tissues and may progress through stages or arise de novo. Diagnostic challenges arise from the historical variety of terms used to describe extranodal natural killer/T-cell lymphoma, including midline lethal granuloma and lymphomatoid granulomatosis.¹³

The Diagnosis: Blastic Plasmacytoid Dendritic Cell Neoplasm

Cutaneous plasmacytoma initially was suspected because of the patient’s history of monoclonal gammopathy as well as angiosarcoma due to the purpuric vascular appearance of the lesions. However, histopathology revealed a pleomorphic cellular dermal infiltrate characterized by atypical cells with mediumlarge nuclei, fine chromatin, and small nucleoli; the cells also had little cytoplasm (Figure). The infiltrate did not involve the epidermis but extended into the subcutaneous tissue. Immunohistochemistry revealed that the cells were positive for CD45, CD43, CD4, CD7, CD56, CD123, CD33, T-cell leukemia/lymphoma protein 1, and CD68. The cells were negative for CD2, CD3, CD5, CD8, T-cell intracellular antigen 1, CD13, CD15, CD19, CD20, CD21, CD23, cyclin D1, Bcl-2, Bcl-6, CD10, PAX5, MUM1, lysozyme, myeloperoxidase, perforin, granzyme B, CD57, CD34, CD117, terminal deoxynucleotidyl transferase, activin receptorlike kinase 1 βF1, Epstein-Barr virus– encoded small RNA, CD30, CD163, and pancytokeratin. Thus, the clinical and histopathologic findings led to a diagnosis of blastic plasmacytoid dendritic cell neoplasm (BPDCN), a rare and aggressive hematologic malignancy.

Blastic plasmacytoid dendritic cell neoplasm affects males older than 60 years.¹ It is characterized by the clonal proliferation of precursor plasmacytoid dendritic cells—otherwise known as professional type I interferonproducing cells or plasmacytoid monocytes—of myeloid origin. Plasmacytoid dendritic cells have been renamed on several occasions, reflecting uncertainties of their histogenesis. The diagnosis of BPDCN requires a biopsy showing the morphology of plasmacytoid dendritic blast cells and immunophenotypic criteria established by either immunohistochemistry or flow cytometry.^2,3 Tumor cells morphologically show an immature blastic appearance, and the diagnosis rests upon the demonstration of CD4 and CD56, together with markers more restricted to plasmacytoid dendritic cells (eg, BDCA-2, CD123, T-cell leukemia/lymphoma protein 1, CD2AP, BCL11A) and negativity for lymphoid and myeloid lineage–associated antigens.^1,4

Blastic plasmacytoid dendritic cell neoplasms account for less than 1% of all hematopoietic neoplasms. Cutaneous lesions occur in 64% of patients with the disease and often are the reason patients seek medical care.⁵ Clinical findings include numerous erythematous and violaceous papules, nodules, and plaques that resemble purpura or vasculitis. Cutaneous lesions can vary in size from a few millimeters to 10 cm and vary in color. Moreover, patients often present with bruiselike patches, disseminated lesions, or mucosal lesions.¹ Extracutaneous involvement includes lymphadenopathy, splenomegaly, and cytopenia caused by bone marrow infiltration, which may be present at diagnosis or during disease progression. Bone marrow involvement often is present with thrombocytopenia, anemia, and neutropenia. One-third of patients with BPDCN have central nervous system involvement and no disease relapse.⁶ Other affected sites include the liver, lungs, tonsils, soft tissues, and eyes. Patients with BPDCN may present with a history of myeloid neoplasms, such as acute/chronic myeloid leukemia, chronic myelomonocytic leukemia, or myelodysplastic syndrome.⁴ Our case highlights the importance of skin biopsy for making the correct diagnosis, as BPDCN manifests with cutaneous lesions that are nonspecific for neoplastic or nonneoplastic etiologies.

Given the aggressive nature of BPDCN, along with its potential for acute leukemic transformation, treatment has been challenging due to both poor response rates and lack of consensus and treatment strategies. Historically, patients who have received high-dose acute leukemia–based chemotherapy followed by an allogeneic stem cell transplant during the first remission appeared to have the best outcomes.⁷ Conventional treatments have included surgical excision with radiation and various leukemia-based chemotherapy regimens, with hyper- CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone-methotrexate, and cytarabine) being the most commonly used regimen.^7,8 Venetoclax, a B-cell lymphoma 2 protein inhibitor, has shown promise when used in combination with hyper-CVAD. For older patients who may not tolerate aggressive chemotherapy, hypomethylating agents are preferred for their tolerability. Although tagraxofusp, a CD123-directed cytotoxin, has been utilized, Sapienza et al⁹ demonstrated an association with capillary leak syndrome.

Leukemia cutis is characterized by infiltration of the skin by malignant leukocytes, often associated with a prior diagnosis of systemic leukemia or myelodysplasia. Extramedullary accumulation of leukemic cells typically is referred to as myeloid sarcoma, while leukemia cutis serves as a general term for specific skin involvement.¹⁰ In rare instances, cutaneous lesions may manifest as the initial sign of systemic disease.

Cutaneous T-cell lymphomas comprise a diverse group of non-Hodgkin lymphomas that manifest as malignant monoclonal T-lymphocyte infiltration in the skin. Mycosis fungoides, Sézary syndrome, and primary cutaneous peripheral T-cell lymphomas are among the key subtypes. Histologically, differentiating these conditions from benign inflammatory disorders can be challenging due to subtle features such as haloed lymphocytes, epidermotropism, and Pautrier microabscesses seen in mycosis fungoides.¹¹

Multiple myeloma involves monoclonal plasma cell proliferation, primarily affecting bone and bone marrow. Extramedullary plasmacytomas can occur outside these sites through hematogenous spread or adjacent infiltration, while metastatic plasmacytomas result from metastasis. Cutaneous plasmacytomas may arise from hematogenous dissemination or infiltration from neighboring structures.¹²

Extranodal natural killer/T-cell lymphoma, nasal type, manifests as aggressive mid-facial necrotizing lesions with extranodal involvement, notably in the nasal/paranasal area. These lesions can cause local destruction of cartilage, bone, and soft tissues and may progress through stages or arise de novo. Diagnostic challenges arise from the historical variety of terms used to describe extranodal natural killer/T-cell lymphoma, including midline lethal granuloma and lymphomatoid granulomatosis.¹³

The Diagnosis: Blastic Plasmacytoid Dendritic Cell Neoplasm

Cutaneous plasmacytoma initially was suspected because of the patient’s history of monoclonal gammopathy as well as angiosarcoma due to the purpuric vascular appearance of the lesions. However, histopathology revealed a pleomorphic cellular dermal infiltrate characterized by atypical cells with mediumlarge nuclei, fine chromatin, and small nucleoli; the cells also had little cytoplasm (Figure). The infiltrate did not involve the epidermis but extended into the subcutaneous tissue. Immunohistochemistry revealed that the cells were positive for CD45, CD43, CD4, CD7, CD56, CD123, CD33, T-cell leukemia/lymphoma protein 1, and CD68. The cells were negative for CD2, CD3, CD5, CD8, T-cell intracellular antigen 1, CD13, CD15, CD19, CD20, CD21, CD23, cyclin D1, Bcl-2, Bcl-6, CD10, PAX5, MUM1, lysozyme, myeloperoxidase, perforin, granzyme B, CD57, CD34, CD117, terminal deoxynucleotidyl transferase, activin receptorlike kinase 1 βF1, Epstein-Barr virus– encoded small RNA, CD30, CD163, and pancytokeratin. Thus, the clinical and histopathologic findings led to a diagnosis of blastic plasmacytoid dendritic cell neoplasm (BPDCN), a rare and aggressive hematologic malignancy.

Blastic plasmacytoid dendritic cell neoplasm affects males older than 60 years.¹ It is characterized by the clonal proliferation of precursor plasmacytoid dendritic cells—otherwise known as professional type I interferonproducing cells or plasmacytoid monocytes—of myeloid origin. Plasmacytoid dendritic cells have been renamed on several occasions, reflecting uncertainties of their histogenesis. The diagnosis of BPDCN requires a biopsy showing the morphology of plasmacytoid dendritic blast cells and immunophenotypic criteria established by either immunohistochemistry or flow cytometry.^2,3 Tumor cells morphologically show an immature blastic appearance, and the diagnosis rests upon the demonstration of CD4 and CD56, together with markers more restricted to plasmacytoid dendritic cells (eg, BDCA-2, CD123, T-cell leukemia/lymphoma protein 1, CD2AP, BCL11A) and negativity for lymphoid and myeloid lineage–associated antigens.^1,4

Blastic plasmacytoid dendritic cell neoplasms account for less than 1% of all hematopoietic neoplasms. Cutaneous lesions occur in 64% of patients with the disease and often are the reason patients seek medical care.⁵ Clinical findings include numerous erythematous and violaceous papules, nodules, and plaques that resemble purpura or vasculitis. Cutaneous lesions can vary in size from a few millimeters to 10 cm and vary in color. Moreover, patients often present with bruiselike patches, disseminated lesions, or mucosal lesions.¹ Extracutaneous involvement includes lymphadenopathy, splenomegaly, and cytopenia caused by bone marrow infiltration, which may be present at diagnosis or during disease progression. Bone marrow involvement often is present with thrombocytopenia, anemia, and neutropenia. One-third of patients with BPDCN have central nervous system involvement and no disease relapse.⁶ Other affected sites include the liver, lungs, tonsils, soft tissues, and eyes. Patients with BPDCN may present with a history of myeloid neoplasms, such as acute/chronic myeloid leukemia, chronic myelomonocytic leukemia, or myelodysplastic syndrome.⁴ Our case highlights the importance of skin biopsy for making the correct diagnosis, as BPDCN manifests with cutaneous lesions that are nonspecific for neoplastic or nonneoplastic etiologies.

Given the aggressive nature of BPDCN, along with its potential for acute leukemic transformation, treatment has been challenging due to both poor response rates and lack of consensus and treatment strategies. Historically, patients who have received high-dose acute leukemia–based chemotherapy followed by an allogeneic stem cell transplant during the first remission appeared to have the best outcomes.⁷ Conventional treatments have included surgical excision with radiation and various leukemia-based chemotherapy regimens, with hyper- CVAD (fractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone-methotrexate, and cytarabine) being the most commonly used regimen.^7,8 Venetoclax, a B-cell lymphoma 2 protein inhibitor, has shown promise when used in combination with hyper-CVAD. For older patients who may not tolerate aggressive chemotherapy, hypomethylating agents are preferred for their tolerability. Although tagraxofusp, a CD123-directed cytotoxin, has been utilized, Sapienza et al⁹ demonstrated an association with capillary leak syndrome.

Leukemia cutis is characterized by infiltration of the skin by malignant leukocytes, often associated with a prior diagnosis of systemic leukemia or myelodysplasia. Extramedullary accumulation of leukemic cells typically is referred to as myeloid sarcoma, while leukemia cutis serves as a general term for specific skin involvement.¹⁰ In rare instances, cutaneous lesions may manifest as the initial sign of systemic disease.

Cutaneous T-cell lymphomas comprise a diverse group of non-Hodgkin lymphomas that manifest as malignant monoclonal T-lymphocyte infiltration in the skin. Mycosis fungoides, Sézary syndrome, and primary cutaneous peripheral T-cell lymphomas are among the key subtypes. Histologically, differentiating these conditions from benign inflammatory disorders can be challenging due to subtle features such as haloed lymphocytes, epidermotropism, and Pautrier microabscesses seen in mycosis fungoides.¹¹

Multiple myeloma involves monoclonal plasma cell proliferation, primarily affecting bone and bone marrow. Extramedullary plasmacytomas can occur outside these sites through hematogenous spread or adjacent infiltration, while metastatic plasmacytomas result from metastasis. Cutaneous plasmacytomas may arise from hematogenous dissemination or infiltration from neighboring structures.¹²

Extranodal natural killer/T-cell lymphoma, nasal type, manifests as aggressive mid-facial necrotizing lesions with extranodal involvement, notably in the nasal/paranasal area. These lesions can cause local destruction of cartilage, bone, and soft tissues and may progress through stages or arise de novo. Diagnostic challenges arise from the historical variety of terms used to describe extranodal natural killer/T-cell lymphoma, including midline lethal granuloma and lymphomatoid granulomatosis.¹³