Histopathologic Diagnosis of H. pylori Infection and Associated Gastric Diseases

Abstract

Helicobacter pylori (H. pylori) can be diagnosed by histopathologic examination which is considered to be a standard method, since not only it observes H. pylori directly but also it evaluates the degree of gastric inflammation, gastritis-related intestinal metaplasia, atrophic gastritis, and tumor. Among various staining methods, hematoxylin and eosin (H&E) stain is a routine procedure in daily practice. However, if H&E stain is not enough for histological diagnosis, ancillary tests including special staining and immunohistochemistry (IHC) are needed for accurate diagnosis. Among various ancillary tests, Giemsa stain has high sensitivity, and silver stain and IHC have high sensitivity and specificity. The initial stage of H. pylori infection is mostly asymptomatic, but it can develop into acute and chronic gastritis. H. pylori-related chronic gastritis shows not only lymphocyte and plasma cell infiltration but also neutrophil infiltration inside epithelium. H. pylori-related chronic gastritis can lead to sequelae, such as atrophic gastritis, intestinal metaplasia, and lymphoid follicles. Moreover, H. pylori infection is a cause of mucosa-associated lymphoid tissue (MALT) lymphoma and gastric cancer, and especially the infection has a close relationship with extranodal marginal zone B lymphoma of MALT and intestinal-type gastric adenocarcinoma. Therefore, histopathologic diagnosis is necessary for gastritis patients, and it should include the degree of gastritis and the presence of H. pylori, sequela of gastritis, and malignant tumor.