[The "depressed adenoma" of the stomach]

Depressed adenoma of the stomach, whose gross appearance is similar to that of type IIc early gastric carcinoma, was detected in 40/357, or 11%, of gastric resection preparations. Depressed adenoma is primarily found in the two distal thirds and the lesser curvature of the stomach. It presents as a flat brownish depression and measures between 2 and 39 mm across (mean 13 mm). Histology typically reveals tubular adenoma with closely spaced atypical columnar epithelial cells of the intestinal type. Depressed adenoma probably arises from pre-existing depressed lesions (erosions, ulcer scars, atrophic zones) rather than from conventional protuberant adenoma. Depressed adenoma appears to show a greater tendency for malignant differentiation than do conventional adenomas.