A 60-year-old man was admitted to our hospital because of gastric submucosal tumor on upper gastrointestinal endoscopy. He was successfully treated for Helicobacter pylori infection at 57 years old. Contrast CT revealed a mass in the gastric body without metastasis to the lymph nodes nor other organs. EGD showed a submucosal tumor with depressed area on the top in the greater curvature of gastric lower body about 2 cm in diameter. Ultrasound endoscopy showed a uniform hypoechoic mass in the third layer. Biopsy specimens revealed no atypical cells but lymphocyte infiltration. Endoscopic submucosal dissection was performed for the purpose of diagnostic treatment. Pathological findings showed the tumor covered by the normal mucosa was mainly located in the submucosal layer. Poorly differentiated adenocarcinoma was observed with B cell-based lymphocyte infiltration. Immunohistochemical staining showed that the tumor cells were positive for EBER. The horizontal and vertical margin were negative with no lymphovascular infiltration. He underwent additional laparoscopic distal gastrectomy with no residual tumor or lymph node metastasis. Here, we report a case of EBV-associated early gastric carcinoma with lymphoid stoma diagnosed by ESD.
