Precancerous conditions and epithelial dysplasia in the stomach.

A distinction can be made between a precancerous condition and a precancerous lesion. The former is a clinical state associated with a significantly increased risk of cancer, whereas a precancerous lesion is a histopathological abnormality in which cancer is more likely to occur than in its apparently normal counterpart. Up to the present time atrophic gastritis, gastric ulcer, pernicious anaemia, gastric stumps, gastric polyps, and Ménétrier's disease have all been considered as precancerous conditions and lesions of the stomach. Of these, only atrophic gastritis, pernicious anaemia, gastric stumps, and certain types of gastric polyp can now be regarded as having any really significant malignant potential. The precancerous lesion common to these is epithelial dysplasia which can occur in ordinary (foveolar) gastric epithelium as well as in intestinal metaplasia. The criteria for grading dysplasia in gastric epithelium into mild, moderate, and severe grades are given, and attention is drawn to the problems of differentiating inflammatory or regenerative change from mild dysplasia and intramucosal carcinoma from severe dysplasia. The clinical and epidemiological implications of gastric dysplasia are discussed with suggestions for further research.