Spontaneous rupture of a middle colic artery aneurysm arising from superior mesenteric artery dissection: Diagnosis by color Doppler ultrasonography and CT angiography.

Both middle colic artery (MCA) aneurysm and spontaneous dissection of the superior mesenteric artery (SMA) are rare. We report the first case of concomitancy of both conditions, diagnosed by ultrasonography and CT angiography. A 56-year-old man with abrupt abdominal pain and hypovolemic shock was diagnosed initially with ruptured MCA aneurysm by color Doppler ultrasonography. Computed tomography and angiography confirmed MCA aneurysm and showed that it was arising from the false lumen of an SMA dissection and was probably associated with segmental arterial mediolysis. The MCA aneurysm was treated successfully by transcatheter coil embolization, and the SMA dissection was treated conservatively.