ADENOCARCINOMA OF COMBINED WITH GASTRIC AND INTESTINAL MUCIN PHENOTYPE ARISING FROM A HUGE PYLORIC GLAND ADENOMA

Abstract

An 80-year-old woman presented for further evaluation of a huge gastric tumor. Esophagogastroduodenoscopy revealed a huge tumor at the gastric fundus and upper body. The tumor appeared as a protruding papillary mass surrounded by a flat elevated lesion. Based on the endoscopic findings, we diagnosed the lesion as a pyloric gland adenoma; however, we suspected that the protruding lesion included a concurrent carcinomatous component and therefore performed laparoscopic total gastrectomy. Histopathological evaluation of the protruding lesion showed findings of a pyloric gland adenoma and well-differentiated adenocarcinoma. The adenocarcinoma component showed papillary morphology combined with gastric and intestinal mucin phenotype. The surface layer of the flat elevated lesion showed tumor cell differentiation into foveolar epithelium, and the middle layer showed cells that were differentiated into pyloric glands. We diagnosed the tumor as an adenocarcinoma that originated from a pyloric gland adenoma. We report a rare case of an adenocarcinoma of combined with gastric and intestinal mucin phenotype that originated from a huge pyloric gland adenoma.