Intracavernous aneurysm with isolated 6th nerve palsy.

A 35-year-old white man with a history of migraine and acute isolated 6th nerve palsy was found to have a large intracavernous aneurysm of the carotid artery. The case demonstrates that a 6th nerve palsy may infrequently be due to an intracavernous aneurysm and, therefore, one should rule out this and other intracranial lesions or systemic disease before accepting the diagnosis of ophthalmoplegic migraine.