Delayed Post-Traumatic Temporal Bone Encephalocele With Lateral Ventricle Herniation.

The main objective of this report was to describe a very unique clinical case of a post-traumatic temporal bone encephalocele with lateral ventricle herniation. This report involves a 60 year-old male who initially presented with right-sided hearing loss, otorrhea, and clear rhinorrhea with metallic taste and a history of a temporal bone fracture managed conservatively 6 years prior to presentation. Computed tomography (CT) revealed a large right tegmen defect and magnetic resonance imaging demonstrated herniation of a significantly-distended lateral ventricle into the mastoid cavity. The patient underwent a combined transmastoid and middle fossa approach for encephalocele removal and tegmen repair. However, 3 months later, follow-up CT scan showed an asymptomatic subacute subdural hematoma (SDH) managed with successful bur hole drainage. Long-term follow-up especially in large skull base defects is critical to monitor delayed occurrence of encephalocele and/or cerebrospinal fluid (CSF) leak. Surgical repair with the removal of devitalized brain tissue and multilayer closure may result in the development of subacute SDH after successful repair.