Morphological range of hyperplastic polyps and carcinomas arising in hyperplastic polyps of the stomach.

A morphological range of 67 hyperplastic polyps was studied. They included polyps removed endoscopically and polyps found incidentally in resected stomachs with gastric ulcers and cancer. The hyperplastic polyps were essentially composed of cystic foveolae and pyloric type glands, lined by cells identical to those of the normal gastric mucosa. Thirty one polyps contained other cytological elements. In 18, intestinal metaplasia was seen; the tubules were mostly composed of columnar and goblet cells and lacked Paneth cells. In 11 polyps, nine cases of gastric dysplasia and two cases of intestinal dysplasia, dysplastic changes were found. The former consisted of a proliferation of irregularly shaped pits with pleomorphic cuboidal/columnar cells with relatively basophilic cytoplasm. They contained mucigen granules of a gastric type. The latter consisted of atypical pits composed of closely packed, tall columnar and small goblet cells, both resembling adenomatous cells of the colon. In three polyps carcinomas were seen, one of which was an intestinal type adenocarcinoma. In the other two, the cancer cells closely resembled the normal foveolar cells, containing gastric type mucigen granules. They were gastric type adenocarcinomas.