The case shows the typical appearance of an arachnoid cyst in an atypical location, so-called intraventricular arachnoid cysts (although strictly-speaking they are not all true arachnoid cysts histologically, please see article for more detail).

It is rarely symptomatic however may cause seizures, especially if localized to the trigone of the lateral ventricle and causing obstructive hydrocephalus of the temporal horn.