Human gastric carcinoid detected during long-term antiulcer therapy of H2 receptor antagonist and proton pump inhibitor

Long-term administration of H2-receptor antagonists or proton pump inhibitors induces the development of gastric carcinoid in rodents, but such effects are thought unlikely to occur in humans. In this report, we present an extremely rare case of a small gastric carcinoid detected during long- term treatment with these drugs. A 31-year-old man received four courses of antiulcer treatments (famotidine, omeprazole and lansoprazole) over 38 months due to recurrent peptic ulcers. A small submucosal nodule was found in the upper body of the stomach following 35 months of treatment. Hispathological examination of the resected specimen revealed an argyrophil-positive carcinoid tumor. Retrospective study of the follow-up gastroscopies suggested the development and growth of this carcinoid during the treatments. These observations suggest that achlorhydria and subsequent hypergastrinemia induced by potent acid-inhibitory drugs could promote development of gastric carcinoid in some patients.