A case is reported of a 54-year-old female patient undergoing the resection of a pancreatic carcinoma with intraoperative radiation therapy (10 Gy) on the tumor bed and subsequent external beam radiotherapy (50 Gy). After surgery the patient presented chronic diarrhea resistant to oral pancreatic enzymes. Twenty-five months postoperatively, mesenteric vein thrombosis was diagnosed after an episode of melena and was treated with conservative therapy. At five-year follow-up the patient had no evidence of neoplastic disease and bowel movements had increased. On imaging examinations, the presence of venous collaterals and cavernous appearance of the portal trunk were documented.