Multifocal gastric carcinoid tumours, achlorhydria, and hypergastrinaemia.

Multiple polypoidal carcinoid tumours of the stomach were found in 5 patients with achlorhydria (4 of whom had pernicious anaemia) as a result of autoimmune atrophic gastritis. The tumours were small (nearly all less than 1 cm diameter) and appeared to grow very slowly, if at all; no significant enlargement or complications were seen during periods of observation of up to 6 years. No extragastric hormonal syndromes were identified. They differed from the carcinoid tumours usually found in the intestinal tract by being composed of argyrophil (not argentaffin) cells of the enterochromaffin-like (ECL) type. Fasting plasma levels of gastrin, which is believed to be trophic to ECL cells, were very high in all patients. Thus, chronic hyperplasia of gastric ECL cells (as a result of hypergastrinaemia) may have been responsible for development of the tumours. Long-term, uninterrupted achlorhydria produced by potent inhibitors of gastric acid secretion might therefore predispose to carcinoid tumours of the stomach.