Primary Petrous Apex Epidermoids With Skull Base Erosion

Petrous apex epidermoid cyst: A rare case

Epidermoid cysts are rare intracranial lesions comprising approximately 1% of all brain tumors, with petrous apex involvement accounting for 4%-9% of cases. These congenital lesions arise from ectodermal remnants during neural tube closure, while acquired cases may result from trauma or chronic middle ear pathology. Clinical presentation is variable and depends on the lesion's location and impact on surrounding neurovascular structures, with cranial nerve dysfunction being the most common symptom. Imaging plays a crucial role in diagnosis, with diffusion-weighted MRI distinguishing epidermoid cysts from other lesions such as arachnoid cysts and cholesterol granulomas. Management remains challenging due to their proximity to critical structures; complete surgical excision minimizes recurrence but may increase morbidity, while subtotal resection requires long-term follow-up. We report the case of a 40-year-old female patient who presented with a history of progressive hearing loss and facial paralysis, in whom an epidermoid cyst of the petrous apex was diagnosed.