Duodenal Somatostatinoma: A Case Report and Review

Somatostatinomas are rare functioning carcinoid tumors that usually arise in the pancreas and duodenum. They are seldom associated with typical clinical symptoms; their diagnosis is confirmed only by histological and immunohistochemical studies and the presence of specific hormones. Two distinct clinicopathological forms of somatostatinoma exist: duodenal and pancreatic somatostatinomas. Clinically, compared to pancreatic somatostatinomas, duodenal somatostatinomas are more often associated with nonspecific symptoms and neurofibromatosis, but less often with somatostatinoma syndrome or metastasis. Histologically, duodenal somatostatinomas frequently have psammoma bodies in the tumor cells. We report a case of duodenal somatostatinoma in 58-year-old man with vague epigastric pain and nausea. He did not have diabetes, steatorrhea, or cholelithiasis. Abdominal computed tomography showed a 25-mm mass in the duodenum and 25-mm nodule in the liver. Endoscopic retrograde cholangiopancreatography showed a duodenal submucosal tumor. Although the endoscopic biopsies were free of malignancy, the patient subsequently underwent Whipple's operation for the duodenal mass. Examination revealed as a somatostatinoma using a special stain for somatostatin.