Pancreatic adenocarcinoma arising from main duct intraductal papillary mucinous neoplasm with inadvertent main pancreatic duct stenting.
The FNA was positive for carcinoma with abundant mucin, which, taken together with the imaging findings, was indicative of pancreatic adenocarcinoma arising from main duct intraductal papillary mucinous neoplasm (M-IPMN).
The post-endoscopic retrograde cholangiopancreatography (ERCP) CT revealed inadvertent placement of the fully covered self-expanding metallic stent (fcSEMS) within the main pancreatic duct (MPD) stricture and persistent common bile duct (CBD) obstruction. On post hoc review of the fluoroscopic and cross-sectional imaging, it became evident that the massively dilated MPD was mistaken during ERCP for the CBD and left hepatic duct (Figure F). In addition, the patient also had several cysts within the liver (compatible with incidental polycystic liver disease), which further complicated real-time image interpretation.
Based on multidisciplinary discussion, the precedent of a prior series of successful palliative MPD stenting in the setting of adenocarcinoma,1 and the notable improvement in the patient's steatorrhea and abdominal pain, the initially placed fcSEMS was left in situ across the MPD stricture, and a second fcSEMS was successfully deployed across the CBD stricture (Figure G), resulting in prompt improvement in serum liver tests. The patient was thereafter initiated on palliative chemotherapy with gemcitabine and abraxane and has maintained clinically stable disease for the last 9 months.
M-IPMN is a premalignant condition in which endoscopy plays an important role. In our patient, because of anatomic and morphologic abnormalities, including the massive dilation of the MPD and severe distal biliary compression in the context of an obstructing pancreatic head mass arising from M-IPMN, initial deployment of the fcSEMS occurred unwittingly into the MPD. Little is known about the impact of fcSEMS in the MPD in patients with pancreatic adenocarcinoma, although in select cases, alleviation of pain caused by MPD obstruction and improvement in quality of life have been reported.2,3 In the case of our patient, fcSEMS placement in the MPD indeed led to symptomatic relief as manifested by a decrease in both diarrhea and pain and an increase in appetite; the addition of a fcSEMS in the CBD led to serum liver test normalization and permitted the initiation of chemotherapy. Further studies are needed to examine the outcomes of palliative MPD stenting in patients with obstructing pancreatic malignancies as well as the epidemiology and biology of M-IPMN and associated pancreatic adenocarcinoma in minority populations.
1. Tham TC et al. Am J Gastroenterol. 2000 Apr;95(4):956-60.
2. Grimm IS, Baron TH. Gastroenterology. 2015 Jul;149(1):20-2.
3. Wehrmann T et al. Eur J Gastroenterol Hepatol. 2005 Dec;17(12):1395-400.