Classification of gastric neuroendocrine tumors and its clinicopathologic significance

AIMS:To study the pathologic classification of gastric neuroendocrine tumors and its clinicopathologic significance.METHODS:Paraffin-embedded sections of 52 gastric neuroendocrine tumors including 42 carcinoid tumors, and 10 cases of neuroendocrine carcinoma from 326 patients who underwent resection of stomach carcinomas were studied by immunohistochemical methods including 10 endocrine markers or hormones antibodies and endocrine cells in gastric neuroendocrine tumors and extratumoral mucosa were observed under electromicroscope.RESULTS:The 52 gastric neuroendocrine tumors were divided into three types:(1) Gastrin dependent type of carcinoid (26 cases) accompanied by chronic atrophic gastritis (CAG) and tumor extension limited to the mucosa or submucosa complicated with hypergastrinemia and G cell hyperplasia.This type was consistently preceded by and associated with generalized proliferation of endocrine cells in the extratomoral fundic mucosa.(2)Non-gastrin dependent type of carcinoids (16 cases)associated with neither CAG nor hypergastrinemia. This type was more aggressive; and (3)Neuroendocrie carcinomas (10 cases), which are highly aggressive tumors.CONCLUSIONS:A correct identification of different types of gastric endocrine tumors has major implications for the treatment and prognosis of the patients.