[Anatomo-pathological classification of gastric tumors]

Pathological classification of gastric tumours. The authors propose a pathological classification of gastric tumours based on topography of lesions. The tumours are related to their origin and localization in the gastric wall: mucosal, extramucosal and metastatic. Among the mucosal tumours, the most frequent are benign polyps, mostly of the hyperplastic type. The classification of mucosal malignant tumours (adenocarcinomas) is dual: macroscopic and microscopic. From the macroscopic point of view, the authors recommend Borrman's classification for invasive cancer and Murakami's classification for early cancer. At the microscopic level, they suggest Lauren's classification in intestinal and diffuse forms or Ming's classification in expanding and infiltrating types. The decreasing incidence of gastric adenocarcinomas in Western countries has artificially increased the relative frequency of gastric lymphomas. The differential diagnosis with reactive lymphoïd hyperplasias may sometimes be troublesome for the pathologist. Among extramucosal tumours, the most frequent are stromal tumours, formerly called leiomyomas and leiomyosarcomas; most are benign. The criteria of malignity are: tumour size, focal necrosis, hypercellularity and mitotic index. The metastatic tumours are mostly melanomas and mammary carcinomas.