[A Case of Superior Mesenteric Vein Thrombosis during Administration of Bevacizumab for Rectal Cancer].

A colonoscopy to investigate fecal incontinence revealed a type 3 tumor in the rectum of a 67-year-old man. Histological findings demonstrated rectal adenocarcinoma. CT revealed multiple metastases in the liver, and the patient was diagnosed as having rectal cancer(Rb, Ant, type 3, T3, N3, M1a[H2], cStage Ⅳa). No intestinal stenosis due to the tumor was found, and chemotherapy(FOLFIRI plus bevacizumab)was initiated. After 5 courses of the chemotherapy, a thrombus was found in the superior mesenteric vein on enhanced CT. The patient had no subjective symptoms, and anticoagulation therapy was started after admission. After confirming the shrinkage of the thrombus, laparoscopic abdominoperineal resection(prxD3)was performed to remove the primary tumor. The thrombus did not grow during the perioperative time and disappeared after 6 months. For the next 2 years, no new thrombus was detected. Mesenteric vein thrombosis is a notable complication of chemotherapy with bevacizumab.