Arachnoid Cyst Causing Third Cranial Nerve Palsy Manifesting as Isolated Internal Ophthalmoplegia and Iris Cholinergic Supersensitivity

Abstract

An 8-month-old boy presented with anisocoria, a sluggishly reactive right pupil, and cholinergic supersensitivity as the only signs of what proved months later to be compressive third cranial nerve palsy due to an arachnoid cyst. Tonic constriction and dilation, segmental iris sphincter palsy, aberrant regeneration phenomena, ductional deficits, and ptosis were absent. The initial diagnosis was postganglionic internal ophthalmoplegia attributed to a viral ciliary ganglionopathy. Nineteen months later, he had developed an incomitant exodeviation and a supraduction deficit. Brain MRI revealed a mass consistent with an arachnoid cyst compressing the third cranial nerve in the right interpeduncular cistern. Resection of the cyst led to a persistent complete third cranial nerve palsy. This is the second reported case of prolonged internal ophthalmoplegia in a young child as a manifestation of a compressive third cranial nerve palsy. Our patient serves as a reminder that isolated internal ophthalmoplegia with cholinergic supersensitivity is compatible with a preganglionic compressive third nerve lesion, particularly in a young child.

Prevalence and natural history of arachnoid cysts in adults

“…20,58,86 This is especially true in the case of common symptoms such as headaches, which arise frequently in the general population. Intracranial arachnoid cysts may occasionally cause hydrocephalus, 39,45,56,60,72,106 cranial neuropathy, 6,29,42,52,55,58,87 seizures, 30,37,45,48,55,58,68,106 headaches, 29,38,45,55,58,72 cognitive complaints, 29,30,38,45,97,98,100 or other focal neurological deficits such as hemiparesis, 29,55 visual compromise, 4,29,45,55,68,72 or cerebellar complaints. 29,68 Cysts in certain locations, such as suprasellar 56 and CPA cysts, appear to be significantly more likely to cause symptoms than cysts in ...…”

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

“…Additionally, there are reports of arachnoid cysts of the cavernous sinus presenting with third nerve palsies; [3] however, these lesions are far distal to the lesion discussed in this case report. A complete discussion of cavernous sinus arachnoid cysts is beyond the scope of this report.…”

Arachnoid Cyst in Oculomotor Cistern

“…So, the oculomotor nerve can be compressed by the arachnoid cyst along any location in its course. Ashker et al (11) reported a case of an arachnoid cyst compressing the oculomotor nerve in the right interpeduncular cistern. Also, Cheng et al (12) reported a case of the arachnoid cyst in cavernous sinus, causing deterioration of visual acuity.…”