Acute ischemic stroke caused by compression of the artery of Percheron by arachnoid cyst.

Ischemic stroke is a rare presentation for intracranial mass lesions in children. It has been described in association with intrasellar tumours, especially with pituitary adenomas and less frequently with craniopharyngiomas. Vascular events have been exceptionally described in association with arachnoid cysts, with only three cases reported. We present here a unique case of a paediatric intraventricular arachnoid cyst that spread both intraventricularly (right trigone) and intracisternally (quadrigeminal plate) and presented as an acute ischemic stroke, secondary to compression of the artery of Percheron, an anatomic variant in which a single dominant thalamoperforating artery supplies variable portions of the upper midbrain and paramedian thalami on both sides. The patient presented with diplopia, left facial nerve palsy, ataxia, and paralysis of upward gaze. He was treated with urgent endoscopic fenestration and antiplatelet agents and made a full clinical recovery.