Giant intracavernous aneurysm: rare cause of isolated sixth cranial nerve palsy in a child.

A boy, aged 7 1/2 years, developed a sixth cranial nerve palsy for which no cause was found until 8 1/2 years later, when he developed a rapidly progressive ophthalmoplegia. A giant intracavernous aneurysm was then demonstrated on carotid angiography and successfully treated by carotid ligation. Radioisotope techniques were of value in diagnosis and follow-up.