Pathology and differential diagnosis of chronic, noninfectious gastritis.

The histologic finding of chronic inflammation in an endoscopic mucosal biopsy of the stomach (chronic gastritis) is very common and usually reflects the presence of Helicobacter pylori infection. However, infectious organisms are not always present in biopsy material, and some cases of chronic gastritis do not result from H. pylori infection. Thus, the differential diagnosis of this finding is an important one for pathologists to keep in mind. This review presents the three most common and clinically significant causes of chronic, noninfectious gastritis, namely, autoimmune atrophic gastritis, lymphocytic gastritis, and gastric involvement in the setting of inflammatory bowel disease, especially Crohn disease. For each entity, a brief discussion of its etiology and pathogenesis, a review of the clinical and endoscopic features, and a description of the microscopic findings are presented in the context of the differential diagnosis of chronic gastritis with emphasis on helpful histopathologic hints and long-term sequelae.