The patient was a 64-year-old woman. She was referred to our institute because of a chief complaint of upper abdominal pain. Abdominal computed tomographic scan revealed a 35 mm hypovascular tumor in the pancreatic head and superior mesenteric vein (SMV), as well as thrombosis. We chose neoadjuvant chemoradiation therapy (NACRT) (S-1/RT, 50.4 Gy/28 Fr) and anticoagulants. After the treatment, the primary lesion showed a partial response, and the SMV thrombosis was reduced. We performed pancreaticoduodenectomy. Histopathological examination revealed no cancer cells in the pancreas. Pathological evaluation revealed grade Ⅳ tumor according to the Evans classification. The patient had had no recurrence for 10 months after the pancreaticoduodenectomy.