Background: Dissecting aneurysms of the vertebrobasilar artery have been increasingly reported. However, those of the anterior circulation are still rare lesions. Those confined to the anterior cerebral artery are extremely rare and their clinical features are not well known.
Case report: Two cases of spontaneous dissecting aneurysm of the anterior cerebral artery are described. Both patients are middle-aged males and presented with ischemic attacks, although they were lacking any factors correlated to atherosclerosis. Definite diagnosis was made by angiography, which demonstrated characteristics of dissecting aneurysm, such as "double lumen" and "string sign." Serial angiography was performed and revealed dynamic changes during the time course. Nonsurgical therapy was utilized and both patients achieved good recovery.
Conclusion: Most of the dissecting aneurysms confined to the anterior cerebral artery present with ischemic attacks. Although their etiology remains uncertain, such aneurysms may be a potent cause of occlusive diseases of the anterior cerebral artery, especially in relatively young males lacking any factors correlated to atherosclerosis.