Multiple carcinoid tumor combined with mucosal carcinoma in the stomach. A case report.

A case of gastric multiple carcinoid tumor combined with mucosal carcinoma in a 63-year-old female is reported. The carcinoid tumors, larger than 0.5 mm in diameter, and endocrine cell micronests, smaller than 0.5 mm in diameter, were mostly located in areas of chronic atrophic gastritis. Their distribution was coincident with that of multiple carcinoid tumor in type A gastritis. The majority of the tumor cells were positive for human chorionic gonadotropin (HCG) and Leu 7 by immunohistochemistry and contained various numbers of intracytoplasmic secretory granules as revealed by electron microscopy. Two mucosal carcinoma foci did not show endocrine characteristics. These carcinoid tumors were thought to have originated in HCG-producing argyrophil cells which had been stimulated by hypergastrinemia accompanying chronic atrophic gastritis. The mucosal carcinomas were regarded as incidental.