Recognizing atrophy: another step toward a classification of gastritis.

The Sydney System is a novel classification of gastritis that attempts to incorporate etiologic, topographic, and morphologic criteria into a clinically relevant scheme. In September of 1994, a group of 20 gastric pathologists from various parts of the world gathered in Houston, Texas, U.S.A., to reappraise the Sydney System 4 years after its introduction and to attempt to reach a broad consensus on gastritis. One of the most controversial issues at the Houston Workshop was the concept of atrophy. Several factors converge to foment confusion and disagreement. "Normal" is imprecisely defined; the loss of glands occurs with distinct patterns and has different functional significance in antrum and corpus; inflammatory infiltrate and lymphoid follicles in the lamina propria may alter the architecture of the gastric mucosa, particularly in the antrum, making loss especially arduous to discern from mere displacement; the relationship between atrophy and intestinal metaplasia remains incompletely understood; and finally, and perhaps most important, the topographic patterns of distribution and the genesis and evolution of atrophic gastritis have been among the most divisive predicaments in the tumultuous arena of gastritis. This article explores some of the difficulties surrounding the concept of atrophy, summarizes the resolutions made at the Houston Workshop, and presents a novel approach to the histopathologic evaluation of atrophic gastritis.