Carcinoid tumors of the duodenum. A clinicopathologic study of 99 cases.

Ninety-nine carcinoid tumors of the duodenum were studied. Seventy-seven patients were followed up for a mean period of 65 months, 20 tumors were autopsy findings, and two patients were unavailable for follow-up. Sixteen tumors (21%) produced metastases, all discovered initially; 3 patients (4%) died from metastatic disease (mean survival, 37 months postoperatively). Features associated with metastatic risk were involvement of muscularis propria, size greater than 2 cm, and the presence of mitotic figures. For 51 tumors, there was no correlation between immunohistochemical somatostatin and history of diarrhea, cholelithiasis, or diabetes mellitus (somatostatin syndrome). Five tumors were associated with Zollinger-Ellison syndrome and had immunohistochemical gastrin, but in the others there was no correlation between ulcer disease and gastrin positivity. Duodenal carcinoids are indolent, especially when small and localized to the submucosa. Immunohistochemical identification of somatostatin and gastrin has little clinical relevance.