Ultrastructure of intestinal and diffuse type gastric carcinoma.

Samples from 56 resected stomachs, including 28 cases of intestinal and 14 of diffuse type gastric carcinoma, were studied by electron microscopy. The main ultrastructural features of intestinal and diffuse type gastric carcinomas were described and compared to the ultrastructure of normal gastric mucosal cells and cells occurring in intestinal metaplasia of the gastric mucosa. Many similarities were demonstrated between intestinal metaplasia and intestinal type carcinomas. The cells of diffuse type carcinomas closely resembled the goblet cells of intestinal metaplasia. Microvilli, similar to those in the brush border of the intestinal columnar cells, could be demonstrated in the carcinomatous surface epithelium and occasionally also in individually spreading cells of the diffuse type carcinoma. Intracellular cysts with microvilli on the cyst wall were occasionally found in both types of carcinoma. The histogenetic origin of gastric carcinoma was discussed.