Unusual arachnoid cyst involving the third ventricle in an adult: Case report

Introduction: Intracranial arachnoid cysts are rare in adults. We report a large suprasellar arachnoid cyst involving a third ventricle in a 19 year old male. Case report: A 19 year old male with mild cognitive impairment was admitted after an episode of loss of consciousness (LOC). A type 1 suprasellar arachnoid cyst (SAC-1) was diagnosed on CT (CT) and magnetic resonance (MR) imaging. Endoscopic fenestration was performed. At surgery, the cyst wall was noted to be markedly thickened with prominent vascularity. Histopathology showed thickened and densely fibrotic meninges, an unusual feature for an arachnoid cyst. 36 months after surgery, the patient remains asymptomatic. Keywords: Arachnoid cysts, Suprasellar, Intracranial, Adult, Hydrocephalus