Long-term follow-up study on gastric adenoma and its relation to gastric protruded carcinoma.

A total of 191 gastric adenomas in 178 patients was studied macroscopically by endoscopy and histopathologically by endoscopic biopsy. Among the lesions, 85 in 74 patients were followed-up for six months to 12 years. Gastric adenomas were found to be more frequent in the aged, with a rate of 0.1% in the third decade but 3.7% in the ninth decade, on gastroscopic examination. Gastric cancers coexistent with the gastric adenomas were seen in 14 cases (8%), and were more frequent in male than in female patients (sex ratio, 12:2). Only eight of the 85 lesions (9%) revealed macroscopic changes. Four of these showed a reduction in size, while the other four lesions showed enlargement. In 21 of the 85 lesions (25%), histologic changes were observed. Four (5%) changed from moderate dysplasia (Group III) to nondysplastic or intestinal metaplasia (Group I), eight lesions (9%) revealed histologic changes (Group III to IV, or vice versa) without malignant transformation, and nine lesions (11%) showed malignant changes. Neither submucosal invasion nor lymph node metastasis was found. These lesions consisted of carcinoma in situ with small foci in the lesions exhibiting moderate dysplasia, and a gradual transition from severe dysplasia to cancer was seen in resected lesions obtained by endoscopic polypectomy or surgical resection. In addition, a gradual increase in dysplasia of tissue from moderate to severe was revealed by repeated gastroscopic biopsy. These findings suggest that the gastric adenomas underwent malignant changes with gradual transformation from moderate through severe dysplasia.