A 74-year-old man was referred to our hospital for further investigation of a cystic lesion in the pancreatic body, which had been detected by ultrasonography at a local hospital. He was diagnosed as intraductal papillary mucinous neoplasm(IPMN) and further preoperative examinations were conducted. Upper gastrointestinal endoscopy demonstrated a type 0-II c tumor of the greater curvature in the upper third of the stomach. Endoscopic ultrasonography showed no sign of submucosal invasion. Endoscopic submucosal dissection(ESD)was carried out and pathological examination of a specimen revealed well differentiated adenocarcinoma with submucosal invasion, which fulfilled the indication for additional gastrectomy with lymph node dissection. Laparoscopy-assisted proxymal gastrectomy with D1 plus lymph node dissection and distal pancreatectomy with splenectomy was performed. Pathological examination demonstrated intraductal papillary mucious adenoma(IPMA)in the pancreatic body and no residual gastric cancer in a specimen, however 7lymph node metastases from gastric cancer was confirmed(pN3a), including 3 metastatic lymph nodes incidentally-detected adjacent to the pancreatic parenchyma. We report a rare case of early gastric cancer with N3 lymph node metastases, with a brief literature review.