Review article: Gastric atrophy and atrophic gastritis--nebulous concepts in search of a definition.

Epidemiological and biological evidence indicates that atrophic gastritis represents an important risk factor for gastric adenocarcinoma of the intestinal type. To estimate an individual subject's risk of gastric cancer, pathologists should be able to diagnose correctly and reliably assess gastric atrophy. However, both anecdotal evidence and recent studies suggest that pathologists have a low level of agreement on gastric atrophy. Moreover, the terms 'gastric atrophy' and 'atrophic gastritis' remain imprecisely defined, further adding confusion to the histopathological imprecision. The use of visual analogue scales proposed in the recently updated Sydney System for the classification and grading of gastritis may eventually help pathologists achieve a greater degree of interobserver agreement on the histopathological features of gastritis. However, this cannot be achieved in the absence of a stringent and widely accepted definition of atrophy. The purpose of this article is to review briefly the possible pathogenetic pathways leading to the development of atrophic changes in the gastric mucosa, explore the issue of its reversibility, and propose a working definition that could contribute to improved diagnostic reproducibility.