GASTRIC NEUROENDOCRINE CARCINOMA-ASSOCIATED WITH CHRONIC ATROPHIC GASTRITIS TYPE-A

We report a case of gastric neuroendocrine (NE) carcinoma associated w ith chronic atrophic gastritis type A (CAG/A) or reversed atrophic typ e gastritis. A 9 x 6 cm tumor was resected from the stomach to control pain in a 55-year-old Japanese woman with peritoneal dissemination an d metastatic tumors of the liver and ovary. Histologically, the tumor was NE carcinoma which showed an organoid structure, but consisted of NE cells with overt cytological atypia and frequent mitotic activity. Multiple microcarcinoids and NE cell micronests (NECMs) were also obse rved in the atrophic non-neoplastic mucosa of the gastric body. CEA im munoreactivity and a high Ki-67 labeling index were characteristic fea tures of the neoplastic NE cells of the carcinoma. Although most NE tu mors arising from CAG/A are typical carcinoid tumors, the present case illustrates that a high-grade NE carcinoma can develop from diverse N E cell proliferation in association with CAG/A.