Dissecting aneurysm of the anterior cerebral artery causing hemorrhagic infarction

Dissecting aneurysms of the cerebral arteries are infrequent, and they occur preferentially in the middle cerebral, internal carotid, and vertebrobasilar arteries. The anterior cerebral artery (ACA) is usually involved in association with dissection in other locations, but a lesion confined to the ACA is an extremely rare event. No previous reports have well documented the clinical and pathological features of the ACA dissection. Moreover, surgical management for this lesion has not been reported.

A case of dissecting aneurysm confined to the ACA causing hemorrhagic infarction is presented. To prevent subsequent rupture, we employed a trapping procedure 12 days after the onset. A dark purplish discoloration of the right A2 portion was encountered, with an intact anterior communicating complex. The involved vessel was partly sectioned for further pathological examination.

Pathologically, subintimal clots dissected the vascular lumen in the inner layer of the media. Other abnormalities such as deficiency of the internal elastic lamina and medial defects were not found. The postoperative clinical course was not eventful.

This is the first case to document an ACA dissecting aneurysm treated by a direct surgical approach. Spontaneous resolution is not infrequent in cerebral dissection, but subsequent rupture has commonly resulted in poor outcome. Surgical management is thought to be the most effective method to prevent further hemorrhagic event, even for an ACA dissection. Revascularization distal to the compromised artery should be considered whenever necessary.