Reversible transinsular herniation of the lateral ventricle.

We present a 7-year-old boy, with a history of neonatal intraventricular hemorrhage, leading to hydrocephalus with multiple shunt revisions. The current presentation of shunt failure and resultant hydrocephalus was complicated by herniation of the trigone of the lateral ventricle into the posterior fossa. Despite the dramatic radiological appearance, this herniation of the lateral ventricle was not accompanied by any additional clinical signs or symptoms other than those usually attributed to hydrocephalus. Following successful shunt revision, the patient returned to his baseline clinically with the trigone reverting back to its normal position. We also present a second companion case.