Gastric epithelial dysplasia and adenoma: historical review and histological criteria for grading.

Gastric epithelial dysplasia (GED) hypothetically is a straight-forward concept: dysplastic epithelium replacing the normal gastric epithelium of the stomach. However, since its inception several decades ago, the term GED has become progressively complex and confusing because of differences in definitions and nomenclature that have been based on cytological, microscopic, endoscopic, or gross features. This has resulted in the terms "dysplasia," "adenoma," "flat adenoma," and "depressed adenoma." Some authors have also included reactive changes under the term "dysplasia."