Gastric Hyperplastic Polyp with Xanthoma Observed by Magnification Narrow-Band Imaging Endoscopy and Endoscopic Ultrasonography : Report of a Case

Abstract We experienced an extremely rare case of gastric hyperplastic polyp with xanthoma. A 73-year-old Japanese man was transferred to our hospital from a referral hospital for further evaluation of a pedunculated gastric polyp and early gastric cancer. Esophagogastroduodenoscopy (EGD) revealed a yellow-whitish pedunculated polyp arising from the anterior wall of the fornix. Magnification narrow-band imaging (NBI) endoscopy revealed extended and tortuous microcapillaries and a swollen interfoveolar pattern on the polyp's surface, but there was no sign of malignancy. Endoscopic ultrasonography (EUS) revealed an irregularity of the first layer and a thickened second layer. The third layer was intact. A hyperechoic area was seen in the thickened second layer. Endoscopic submucosal dissection (ESD) for early carcinoma of the antrum and endoscopic mucosal resection (EMR) for a polyp in the fornix were performed in one session. Histological examination of the specimen of the fornix polyp revealed lengthened, branched and dilatated gastric foveolae and a tight sheet of foamy histiocytes in the stroma. The background mucosa of the polyp was atrophic. The pathologic evidence was gastric hyperplastic polyp with proliferation of xanthoma. The early cancer of the antrum was intramucosal tubular adenocarcinoma and was resected curatively.