Neuroendocrine tumors of the pancreas and peripancreatic area are rare entities with a wide spectrum of clinical presentation. This study retrospectively reviews the patients who underwent surgery for these tumors at The Johns Hopkins Hospital from 1949 to 1996, inclusive. There were 125 patients (65 males and 60 females) whose mean age was 51 +/- 1 years. Fifty-eight patients (48%) had nonfunctional tumors, whereas 64 (52%) had functional tumors: 35 (55%) insulinomas, 23 (36%) gastrinomas, three (5%) VIP-omas, two (3%) glucagonomas, and one (1%) ACTHoma. All patients with functional tumors presented with appropriate signs and symptoms of hormonal excess; 86% of patients with nonfunctional tumors presented with weight loss, abdominal pain, or jaundice. Preoperative computed tomography (CT) correctly localized the tumor in 66 (76%) of 87 patients; angiography in 45 (58%) of 78 patients; and CT plus angiography in 54 (79%) of 68 patients. Tumors were benign in 60 patients (48%), malignant in 65 patients (52%), and were located in the head, neck, or uncinate process of the pancreas in 54, body in 14, tail in 18, and duodenum in eight. The most common operative procedures performed were 50 pancreaticoduodenectomies (40%), 39 distal pancreatectomies (31%), and 21 tumor enucleations (17%). Nine synchronous hepatic resections were performed for metastases. Of the evaluable patients, 46 (43%) had postoperative complications, the most common of which were pancreatic fistula (16%), wound infection (15%), and delayed gastric emptying (8%). There were three in-hospital deaths (2.8%). With a mean follow-up of 55 +/- 6 months, there have been 30 additional deaths, 23 of which were related to disease progression. The overall 2-, 5-, and 10-year actuarial survival rates were 82%, 65%, and 47%, respectively. The 5-year survival for patients with functional tumors was 77% compared to 52% for those with nonfunctional tumors (P = 0.025); the 5-year survival for patients with benign tumors was 91% compared to 49% for those with malignant tumors (P=0.0004). By univariate analysis the most powerful predictor of poor outcome for patients with malignant tumors (n = 60) was positive surgical margins (P=0.006). This single-institution experience documents low mortality and moderate morbidity for patients treated operatively for pancreatic and peripancreatic neuroendocrine tumors. The most favorable outcomes are observed in patients with benign functional tumors and in those with completely resected malignant tumors.