Clinical Challenges

What's your diagnosis?

Publish date: July 29, 2022
By
Ovanes Abramyan
Nicholas F. Larusso, MD
James H. Tabibian, MD, PhD

A 69-year-old Filipino American woman presented with increasing epigastralgia, worsening appetite, jaundice, and oily diarrhea over the course of 3 months. Her past medical history consisted of diabetes, hypertension, hyperlipidemia, and osteopenia being managed with metformin, losartan, and atorvastatin, respectively.
Physical examination revealed she was thin (body mass index, 22 kg/m2) and jaundiced with moderate tenderness to epigastric palpation and 1+ peripheral pitting edema. Laboratory tests were significant for normal complete blood count and elevated alanine aminotransferase (113 U/L), alkaline phosphatase (235 U/L), bilirubin (7.3 mg/dL), international normalized ratio (1.3), and carbohydrate antigen 19-9 (7886 U/L). A CT scan of the abdomen revealed severe extrahepatic and intrahepatic ductal dilation, with a common bile duct (CBD) and main pancreatic duct (MPD) diameter of 2.5 and 1.7 cm, respectively, as well an infiltrating, malignant-appearing, 4.5-cm spheroid mass in the head of the pancreas (Figure A). The mass involved the superior mesenteric vein at the portal confluence and encased >50% of the superior mesenteric artery.

To further characterize these findings, magnetic resonance cholangiopancreatography was performed, which additionally revealed multifocal cysts throughout the liver ranging from 0.5 to 5.0 cm in greatest diameter, as seen on maximal intensity projection algorithm (Figure B).
The patient was referred for same-session endoscopic ultrasound examination with fine needle aspiration (FNA) and endoscopic retrograde cholangiopancreatography (ERCP) for further diagnosis and treatment. Endoscopic ultrasound demonstrated a large, hypoechoic mass in the pancreatic head with severe CBD and MPD dilation proximally, corresponding with the cross-sectional imaging findings; FNA was performed. ERCP demonstrated a long, distal CBD stricture and what appeared to be nonopacification of the right hepatic ductal system; a 10 × 60-mm fully covered self-expanding metallic stent (fcSEMS) was placed across the stricture (Figure C, D). Over the subsequent 3 days, the patient's diarrhea resolved and epigastralgia improved; however, serum liver tests did not downtrend, thus prompting repeat imaging (Figure E).
Based on the patient's clinical history, cross-sectional imaging findings, and only partial response to therapeutic ERCP, what are the patient's likely diagnoses?


 

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.

References
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.

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