Gastrinomas in the duodenums of patients with multiple endocrine neoplasia type 1 and the Zollinger-Ellison syndrome.

In patients with multiple endocrine neoplasia type 1 (MEN-1), gastrinomas are common and thought to occur predominantly in the pancreas. We describe eight patients with MEN-1 and hypergastrinemia (seven with the Zollinger-Ellison syndrome) in whom we searched for neuroendocrine tumors in the pancreas and duodenum. Tumors were found in the proximal duodenum in all eight patients: solitary tumors (diameter, 6 to 20 mm) in three patients and multiple microtumors (diameter, 2 to 6 mm) in the other five. Paraduodenal lymph-node metastases were detected in four patients. Immunocytochemical analysis revealed the presence of gastrin in all the duodenal tumors and in their lymph-node metastases. In contrast, no immunoreactivity for gastrin was present in the endocrine tumors found in the seven pancreatic specimens available for study, except for one tumor with scattered gastrin-positive cells. In four of the six patients whose duodenal gastrinomas were removed, serum gastrin levels returned to normal; in the other two patients gastrin concentrations decreased toward normal. We conclude that in patients with MEN-1 and the Zollinger-Ellison syndrome, gastrinomas occur in the duodenum, but the tumors may be so small that they escape detection.