Special forms of initial gastric cancer.

1. Fifty-five microscopic cancer foci from 11 gastric resection preparations have been examined. Each focus than 5 mm was less in diameter. They occurred mostly in regions showing chronic atrophic gastritis, less frequently in the margin of peptic ulcer or in a polyp located in the antrum along the lesser curve. The lesions were discovered at routine histologic examination of stomachs operated upon for other primary diseases. 2. Histologically differentiated and undifferentiated types could be distinguished. They were: well differentiated adenocarcinoma, tubular adenocarcinoma, "intraluminal papillary proliferation of the glandular neck", "glandular neck displasia" mucocellular and muconodular carcinoma, and carcinoma in situ. In some cases, different histologic types within the same focus, or more foci of diverse structure in the same patient could be observed. 3. A malignant process developing from the glandular neck region or the surface epithelium could be demonstrated in each type of initial cancer.