Gastric Adenoma

Abstract

Gastric adenoma is defined as "a circumscribed benign neoplasm composed of tubular and/or villous structures lined by dysplastic epithelium." Architecturally, gastric adenomas have been categorized as tubular, tubulovillous, or villous adenoma. By using immunohistochemical staining specific for gastric and intestinal mucins and enzymes, gastrointestinal adenomas can be reclassified based on phenotype. Phenotypically, the majority of gastric adenomas belong to the intestinal type (containing goblet cells, absorptive cells, Paneth cells, and/or columnar cells with various degrees of differentiation). Gastric-type adenomas are predominantly composed of pyloric gland mucous cells (pyloric gland adenoma) or gastric foveolar cells (foveolar-type adenoma). There are clinical and morphologic differences between intestinal-type and gastric-type adenomas. In this review, histology and immunohistochemical characteristics of gastric adenomas are described in relation to cell phenotypes of dysplastic epithelial cells.