Surgical resection for ruptured aneurysm of middle colic artery caused by segmental arterial mediolysis: a case report.

Aneurysm of the middle colic artery is very uncommon. In this report, we describe a case of a ruptured aneurysm of the middle colic artery caused by segmental arterial mediolysis and its successful management by surgical resection. A 60-year-old Japanese man was admitted to our institution for the treatment of a ruptured aneurysm of the branch of the superior mesenteric artery suspected by computed tomography. Angiography revealed multiple wide and narrow mural irregularities and some aneurysms in the middle colic artery without extravasation. Transcatheter arterial embolization could not be accomplished because of difficulty in catheterization. Since radiological findings of the patient indicated worsening of the aneurysm, surgical resection was performed. Histopathological findings of the resected specimen were consistent with those of segmental arterial mediolysis. In cases where curative embolization cannot be accomplished, surgical resection is required. However, in a non-ruptured aneurysm, healing occurs gradually. Therefore, if the vital parameters of the patient are stable, conservative observation can be recommended.