Giant Cephalocele Case Mimicking Cystic Neoplasia in Skull Base

Petrous apex cephalocel, also called arachnoid cyst or meningocele, is a rare cephalocele caused by protrusion of the posterolateral wall of the Meckel cave to the petrous apex. Increased intracranial pressure is thought to play a role in etiopathogenesis and is generally asymptomatic. Radiologically, they are expansile lesions with the same density or intensity as cerebrospinal fluid and may mimic cystic masses. The diagnosis is made by showing the continuity with Meckel cave on magnetic resonance imaging. No intervention is required in asymptomatic patients; surgical treatment is applied in symptomatics.