Gastrinoma of duodenal G‐cell origin

A 65‐year‐old man with hypergastrinemia associated with the Zollinger‐Ellison syndrome was found to have a duodenal “carcinoid‐islet cell tumor.” Gastrin levels have remained normal for more than 1 year following total gastrectomy and removal of the duodenal tumor. Immunohistochemical studies for gastrin localization revealed positive staining of the tumor and of a population of non‐neoplastic G‐cells in the adjacent duodenal mucosa and Brunner's glands. These results support the hypothesis that gastrinomas may arise as primary tumors from duodenal G‐cells rather than from ectopic pancreatic tissue. “Carcinoid‐islet cell tumors,” like other tumors of APUD‐cell origin, may express dual biochemical functions in the form of polypeptide hormone and/or amine secretion. Their content of specific hormonal products may be predicted on the basis of sensitive histochemical and immunohistochemical techniques.