Lymphoepithelioma-like gastric carcinoma resected by endoscopic submucosal dissection (ESD).

thelioma-like gastric carcinoma that presented as a flat depressed lesion and was treated by complete en-bloc resection using endoscopic submucosal dissection (ESD). A 73-year-old manwas referred to the department of internal medicine because of an incidental finding suspicious of early gastric cancer. The patient’s medical history and laboratory test results were unremarkable. Gastroscopy revealed an erythematous, flat depressed lesion in the posterior wall of the upper part of the gastric body (●" Fig. 1). No abnormalities were detected on abdominal computed tomography. The tumor was removed completely by ESD, using an insulation-tipped knife (KD610L; Olympus, Tokyo, Japan) (●" Fig. 2). Histopathological findings of the resected specimen were compatible with the diagnosis of lymphoepithelioma-like gastric carcinoma (●" Fig. 3). Lymphoepithelioma-like gastric carcinoma is a rare type of gastric carcinoma, constituting about 4% of all gastric carcinomas [1]. It is characterized by the presence of a lymphoid stroma and small nests of cancer cells that are uniformly distributed throughout the lymphoid stroma. There is clear demarcation between the tumor nests and the nondesmoplastic lymphocyte-rich stroma, as is the case with lymphoid tissue. Lymphoepithelioma-like gastric carcinoma has a good prognosis and is closely associated with the presence of the Epstein-Barr virus and microsatellite instability [2]. The recently introduced technique of ESD can be useful in the diagnosis and treatment of early gastric cancer. In particular, this method enables en-bloc resection of the tumor, regardless of tumor size and location. In our case, endoscopic examination of the flat depressed lesion revealed an appearance typical of early gastric adenocarcinoma. However, the histological examination revealed that the tumor was a lymphoepithelioma-like gastric carcinoma.