1310 A Rare Case of Biliary Pancreatitis Caused by Ampullary Somatostatinoma in a 46-Year-Old Female

Abstract

INTRODUCTION: Somatostatinoma is a rare neuroendocrine tumor predominantly found in the pancreas and the duodenum and only in 3% of cases within ampulla of Vater. Affected people usually present with abdominal pain, GI bleed, obstructive jaundice or when metabolically active with somatostatin syndrome (DM, diarrhea, cholelithiasis). Somatostatinoma is typically a large malignant tumor usually with metastatic disease on presentation. CASE DESCRIPTION/METHODS: This is a case of a 46-year-old female with a medical history of cholecystectomy, fatty liver and diabetes mellitus who presented with a two-day history of scleral icterus, clay-colored stools and dark urine. On initial evaluation, she was afebrile and normotensive. Her lab work was consistent with acute pancreatitis (lipase 2498 U/L) as well as an obstructive biliary disease (ALP 1210 U/L; bilirubin 6.3 mg/dl; AST 157 U/L; ALT 153 U/L). CT scan of the abdomen showed a 1.5 cm bulbous irregular ampullary lesion and moderate intra-and extrahepatic as well as pancreatic duct dilation. Further evaluation with EUS revealed a 12 mm × 12.7 mm hypoechoic mass of the ampulla and FNA was obtained. ERCP revealed dilated bile ducts with the possibility of subtle stricture in the distal most portion of the CBD. Brushings were performed and 10 mm × 60 mm fully covered biliary metal stent was deployed with resolution of patient's symptoms and improvement of her liver enzymes. Cytology results from the stricture were negative for malignancy. EUS FNA was positive for neoplastic cells immunoreactive with synaptophysin and somatostatin. Unfortunately, the patient did not follow up until she developed abdominal pain 2 years later. Repeated CT of the abdomen showed 0.9 × 0.6 cm mass in periampullary region decreased in size from previous CT. ERCP revealed epithelization and tissue regrowth in the stent. Two 7 Fr, 7 cm Boston Scientific double-pigtail stents were placed through the previous metal stent with successful decompression. Pancreaticoduodenectomy is scheduled with surgical oncology. DISCUSSION: Somatostatinomas, especially in the ampullary region, may present as painless jaundice leading to acute biliary pancreatitis. Interestingly, even after patient was lost to follow up for 2 years, she did not develop metastatic disease which is usually found with first presentation of the disease. Nevertheless, due to high metastatic potential every case when possible should be treated radically and pancreaticoduodenectomy is the treatment of choice.