Natural history of a spontaneous dissecting aneurysm of the proximal superior mesenteric artery: report of a case.

We report herein the case of a 44-year-old man in whom an asymptomatic dissecting aneurysm was found in the proximal part of the superior mesenteric artery (SMA) during a preoperative evaluation for colon cancer. The patient was managed conservatively with blood pressure control during the perioperative period of the colon resection as the false lumen of the dissecting aneurysm was revealed to be completely occluded by thrombus. The thrombus in the false lumen continued to be absorbed until 1 month after surgery. The patient is currently well 4 years after his operation without any evidence of recurrence of the aneurysm.