Aspirin-induced glandular dysplasia of the stomach: histologic and histochemical studies in rats.

Stomachs of 22 rats treated with aspirin for six months were examined histologically at times ranging from 6 to 18 months after completion of treatment. Healed chronic gastric ulcers were found in 20 rats. Glandular dysplasia was present at the sites of healed ulcers in 12 rats, the glands extending into the submucosa, muscularis propria, and even subserosal fat. The apparent lack of progression with time and the absence of metastases suggest that the changes are not neoplastic but are a consequence of repeated injury and regeneration, with entrapment of glands below the level of the muscularis mucosae. The lesions in the aspirin-treated animals closely resemble those of gastritis cystica polyposa and colitis cystica profunda in the human subject.