Gastric epithelial dysplasia.

Gastric dysplasia is considered to be the penultimate stage of the gastric carcinogenesis sequence. Its clinical importance has been underscored since its association with gastric adenocarcinoma was established. High-grade dysplasia and to a lesser degree low-grade dysplasia are markers of increased cancer risk, although their natural histories are difficult to determine. There are many pitfalls in the diagnosis of gastric dysplasia. Its recognition and grading are subject to interobserver variability, particularly at the lower end of the histologic spectrum (negative v indefinite for dysplasia v low-grade dysplasia) when inflammation is present. Also, diagnostic criteria and grading schemes have evolved differently worldwide resulting in disagreement between pathologists. Against this background, the authors review contemporary issues related to gastric dysplasia, its definition, classification, grading, and natural history. We also discuss new classifications of gastric epithelial dysplasia designed to develop equivalence between grading schemes worldwide.