Which of the following is the most common presenting symptom in patients with a somatostatinoma?
A. CholelithiasisBecause somatostatin inhibits pancreatic and biliary secretions, patients with a somatostatinoma present with gallstones due to bile stasis, diabetes due to inhibition of insulin secretion, and steatorrhea due to inhibition of pancreatic exocrine secretion and bile secretion. Most somatostatinomas originate in the proximal pancreas or the pancreatoduodenal groove, with the ampulla and periampullary area as the most common site ( 60%). The most common presentations are abdominal pain (25%), jaundice (25%), and cholelithiasis (19%). This rare type of pancreatic endocrine tumor is diagnosed by confirming elevated serum somatostatin levels, which are usually above 10 ng/mL. Although most reported cases of somatostatinoma involve metastatic disease, an attempt at complete excision of the tumor and cholecystectomy is warranted in fit patients.