The classification of chronic gastritis: current status.

The importance of classifying chronic gastritis is the causal relationship of some cases to pernicious anemia, peptic ulcer, and gastric adenocarcinoma. The morphology and topographic distribution of chronic gastritis form the basis for the current recognition of five subtypes. These are: Type A or diffuse atrophic corporal; Type B or diffuse antral; Type AB or multifocal atrophic; and Type C chemical, reactive, and lymphocytic. The etiology includes autoimmunity, bacterial infection, bile reflux, the effects of nonsteroidal anti-inflammatory drugs, and diet. There are, however, discrepancies in the evidence that these subtypes are entirely distinct. A multifactorial etiology for individual cases and groups of cases is argued as the cause of difficulty in assigning cases to a specific type. The challenge still posed by chronic gastritis is stressed.