Dissecting aneurysm of the anterior temporal artery: case report.

A 65-year-old woman presented a rare dissecting aneurysm of the anterior temporal artery (ATA) manifesting as headache. Computed tomography and magnetic resonance imaging revealed a mixed-density mass in the horizontal segment of the middle cerebral artery. Emergent angiography demonstrated aneurysmal dilatation and a thrombosed mass in the sylvian fissure. Infectious aneurysm was excluded. She underwent emergent surgery to reduce the risk of repeated infarction and hemorrhage. The distal side of the ATA manifested occlusive changes suggestive of arterial dissection. The proximal side of the ATA was ligated and the lesion was excised. Histological examination confirmed that the aneurysmal dilatation was attributable to arterial dissection due to disruption of the internal elastic lamina. Distal dissecting aneurysms may occur in the absence of infectious disease. We recommend that ruptured distal dissecting aneurysms be treated surgically in the acute stage immediately after detection.