CLINICOPATHOLOGICAL CHARACTERISTICS OF A FOVEOLAR-TYPE GASTRIC NEOPLASM WITH RASPBERRY-LIKE APPEARANCE

Abstract

Foveolar-type gastric neoplasia (adenoma/carcinoma) refers to a gastric epithelial neoplasm with an immunophenotype characterized by gastric foveolar cell differentiation. This neoplasm presents as a small, reddish protruded polyp with a raspberry-like appearance in Helicobacter pylori-naïve gastric mucosa. The lesion commonly occurs in the gastric body or fornix and is small in size (≤5 mm). The papillary or gyrus-like microstructure, which typically shows a wide intervening portion and dilated irregular vessels is best viewed using narrow-band imaging with magnification endoscopy. Histopathologically, the lesion appears as an intraepithelial neoplasm with gastric foveolar cell differentiation. This tumor is usually diagnosed as carcinoma in Japan based on its gastric phenotype; however, it is classified as a foveolar-type gastric adenoma by the World Health Organization classification based on its non-invasiveness. The differential diagnosis in cases of H. pylori-naïve gastric mucosa includes a hyperplastic polyp or hamartoma, which shows similar morphological features; however, magnification endoscopy can distinguish between these lesions.