Facial Nerve Paralysis Revealing a Petrous Apex Cholesteatoma: A Case Report

Petrous apex cholesteatoma is an uncommon entity whose clinical presentation may be subtle or misleading due to the complex anatomy of this region. We report the case of a 64-year-old man initially referred to ophthalmology for a corneal abscess secondary to lagophthalmos, in whom clinical examination revealed a right peripheral facial paralysis (House–Brackmann grade IV) with a normal otoscopic evaluation. Lack of improvement after medical therapy and rehabilitation prompted imaging. MRI demonstrated a right petrous apex lesion, hypointense on T1, intermediate on T2, with marked diffusion restriction, extending to the geniculate ganglion and the labyrinthine segment of the facial nerve. High-resolution CT confirmed erosion of the superior semicircular canal. Overall correlation of clinical and radiologic findings was highly suggestive of petrous apex cholesteatoma. This case highlights the importance of considering petrous apex lesions in unexplained facial paralysis, even when otoscopic findings are normal.