Cavernous internal carotid artery aneurysm presenting with ipsilateral oculomotor nerve palsy: A case report.

The oculomotor nerve palsy is a rare neurological deficit, it is associated with numerous underlying pathologies. Including stroke, neoplasms, trauma, post-surgical inflammation, and microvascular damage from chronic disease. It can cause a set of neurological deficits, including diplopia from oculomotor nerve involvement, decreased visual acuity from optic neuropathy, facial hypoesthesia from involvement of the trigeminal nerve, and less frequently facial pain. We present a case of 52 years old female patient who presented with a history of lateral divination of the left eye associated with ipsilateral drooping of upper eyelid, visual disturbance, and ‏pupil dysfunction. MRI and MRA were performed and in conventional sequences plus 3D FIESTA sequence and it shows a signal void structure, compressing the left oculomotor nerve after passing through left chiasmatic cistern and upon entrance to cavernous sinus. Reformatted images demonstrate that this structure arising from distal left internal carotid artery at lateral part of cavernous sinus represents a saccular aneurysm in the cavernous part of the internal carotid. Aneurysms can cause direct compression of the third cranial nerve either by the enlargement of an unruptured aneurysm or by rupture of the aneurysmal sac resulting in third cranial nerve palsy.