Diagnosis of a neutrophilic dermatosis, such as pyoderma gangrenosum (PG), often is challenging at onset because it can be impossible to distinguish clinically and histopathologically from acute infection in an immunosuppressed patient, necessitating a detailed history as well as correlation pathology with microbial tissue cultures. The dermatologist’s ability to distinguish a neutrophilic dermatosis from active infection is of paramount importance because the decision to treat with surgical debridement, in addition to an antibiotic regimen, can have grave consequences in the misdiagnosed patient.
Pyoderma gangrenosum is a neutrophilic dermatosis histologically characterized by a pandermal neutrophilic infiltrate without evidence of an infectious cause or true vasculitis. It is classically associated with inflammatory bowel disease or an underlying hematologic malignancy. Pyoderma gangrenosum in the setting of chronic lymphocytic leukemia (CLL) is rare, with as few as 4 cases having been described in the literature and only 1 case of PG developing after a surgical procedure.1-4 We present a case of PG occurring at a chest tube site in a patient with CLL. We highlight the challenges and therapeutic importance of arriving at the correct diagnosis.
An 87-year-old man with a history of refractory CLL was admitted to the hospital with pneumonia and pleural effusion requiring chest tube placement (left). His most recent therapeutic regimen for CLL was rituximab and bendamustine, which was administered 9 days prior to admission. After removal of the chest tube, an erythematous plaque with central necrosis surrounding the chest tube site developed (Figure 1A). During this time period, the patient had documented intermittent fevers, leukopenia, and neutropenia. Serial blood cultures yielded no growth. Because the patient was on broad-spectrum antibiotic coverage, dermatology was consulted for possible angioinvasive fungal infection.
Physical examination revealed an indurated, erythematous-violaceous, targetoid, well-defined, ulcerated plaque with central necrosis on the left side of the chest. Notably, we observed an isolated bulla with an erythematous base within the right antecubital fossa at the site of intravenous placement, suggesting pathergy.
Multiple punch biopsies revealed an ulcer with an underlying dense neutrophilic infiltrate within the dermis and subcutaneous tissues (Figure 2). Grocott-Gomori methenamine-silver, periodic acid–Schiff, and acid-fast bacillus stains were all negative for organisms. Tissue cultures for bacterial, fungal, and acid-fast bacilli revealed no growth. Due to the rapidly expanding nature of the plaque and the possibility of infection despite negative microbial stains and cultures, the patient was scheduled for surgical debridement by the surgical team.
Opportunely, after thoughtful consideration of the clinical history, histopathology, and negative tissue cultures, we made a diagnosis of PG, a condition that would have been further exacerbated by debridement and unimproved with antibiotics. Based on our recommendation, the patient received immunosuppressive treatment with prednisone 60 mg/d and triamcinolone ointment 0.1%. He experienced immediate clinical improvement, allowing him to be discharged to the care of dermatology as an outpatient. He continued to receive a monthly rituximab infusion. We intentionally tapered the patient’s prednisone dosage slowly over 4 months and photodocumented steady improvement with eventual resolution of the PG (Figure 1B).