MVD and metastatic malignant neoplasm in the lymph nodes: Final pathological staging was moderately differentiated invasive ductal adenocarcinoma of the pancreas with no lymph node metastasis (Japan Pancreatic Society (JPS) classification 7th edition; Pbt, TS1 (6 mm), tub2, intermediate type, INF β, ly1, v1, ne1, mpd(-), pT1b, pN0, pM0, stage IA,PCM(-), DCM(-) and the Union International Control Cancer (UICC) classification of malignant tumors 6th edition; pT1, pN0, pM0, stage IA, R0).