Parasellar arachnoid cyst presenting with a nonpupil sparing third nerve palsy mimicking a posterior communicating artery aneurysm in an adult

Abstract

Background:Arachnoid cysts are congenital lesions that contain fluid identical to cerebrospinal fluid (CSF). They usually do not communicate with CSF spaces. The vast majority of arachnoid cysts are congenital asymptomatic lesions that are discovered incidentally. Those lesions that do become symptomatic typically present in childhood with signs and symptoms of intracranial hypertension, seizures, and focal neurologic deficits specific to cyst location.Case Description:A rare case of a parasellar arachnoid cyst presenting with oculomotor palsy is presented. The patient is a 45-year-old male who presented with acute onset diplopia and frontal headache. Neurologic examination revealed right ptosis, pupillary dilation, and opthalmoparesis consistent with an oculomotor palsy. Computed tomography (CT) scan and lumbar puncture failed to reveal evidence of a subarachnoid hemorrhage. Magnetic resonance imaging (MRI) of the brain demonstrated a 1 cm right parasellar nonenhancing mass that was hyperintense on T2 flair and with a fluid-fluid level concerning for a thrombosed posterior communicating artery (PCommA) aneurysm. There was an additional finding of a left occipital pole intraparenchymal hemorrhage in the setting of multiple hereditary cavernomas. Formal cerebral angiography revealed normal intracranial and extracranial vasculature. The patient was taken to the operating room for a right frontotemporal craniotomy, which revealed compression of the right oculomotor nerve by an arachnoid cyst. The cyst was fenestrated and resected with decompression of the oculomotor nerve. Postoperatively, the third nerve palsy had completely resolved.Conclusions:The above case demonstrates that arachnoid cysts should be considered in the differential for patients presenting with nonpupil sparing third nerve palsy and require timely surgical intervention. As is the case for an expanding PCommA aneurysm, prompt decompression results in the best chance for recovery of oculomotor nerve function.

Cranial Nerve Palsies in the Setting of Arachnoid Cysts: A Case Series and Literature Review

“…No large-scale study has been performed to determine the comorbidity of ACs and CN palsy, but there is a sizeable case report literature demonstrating their association. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Given the neurologic risk that ACs can present, 1 it is important to develop clear guidelines for their evaluation and treatment.…”

“…Cranial nerve (CN) palsies caused by ACs affecting CN III, IV, and VI have been reported. 2–19 Furthermore, the course of CN III, CN IV, and CN VI involves many structures where ACs have been reported. 1…”

“…Cranial nerve (CN) palsies caused by ACs affecting CN III, IV, and VI have been reported. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Furthermore, the course of CN III, CN IV, and CN VI involves many structures where ACs have been reported. 1 The best treatment approach for symptomatic patients affected by intracranial ACs is contested, 20 and no guidance exists for the management of diplopia caused by ACs.…”

Intracranial varix of the transverse-sigmoid dural arteriovenous fistula mimicking a ruptured middle cerebral artery aneurysm: A case report

“…There are some reports that other bleeding sources, such as DAVF,[ 1 , 3 , 11 , 13 ] cavernomas,[ 18 , 21 ] hemangioblastomas,[ 7 , 15 ] arachnoid cyst,[ 17 ] and gliomas,[ 16 ] were mistaken for an aneurysmal rupture on initial imaging modalities. In addition, venous structures, such as a venous loop, can also be mistaken for aneurysms.…”

Hemorrhagic arachnoid cyst of the suprasellar cistern causing complete third cranial nerve palsy and transient ischemic attacks

“…AC of the suprasellar cistern causing TNP have been reported in a few isolated cases [10,11] including a new entity of "de novo" AC [12].…”