Middle Fossa Meningioma Presenting with External Auditory Canal Mass, Conductive Hearing Loss, and Facial Weakness

Introduction: Meningiomas account for 13–18% of primary brain tumors, with, temporobasal lesions accounting for 4% of all such tumors. Extracranial extension occurs in 20% of meningiomas, but increases to 43% with temporal bone involvement. We describe a rare presentation of meningioma with an external auditory canal (EAC) mass, conductive hearing loss, and facial nerve weakness. Only 8 additional cases of meningioma extension into the EAC are found in the literature. We highlight meningiomas as part of the differential diagnosis in EAC lesions and conductive hearing loss. Our case also underscores the importance of multidisciplinary teams in the management of complex skull base lesions.

Case: A 38-year-old female presented to neurotology clinic with 1 year of progressive right-sided hearing loss and facial weakness. She complained of a dry right eye secondary to her inability to fully close the eye. On examination, she had right-sided House-Brackmann grade IV facial nerve weakness. Otoscopic examination demonstrated a soft, compressible mass occupying the right ear canal and obscuring visualization of the tympanic membrane. An audiogram confirmed a significant right-sided conductive hearing loss with 45 dB air–bone gap and normal left-sided auditory function.

CT of the head revealed diffuse hyperostosis of the petrous temporal bone and bone of the floor of the middle cranial fossa. The middle ear, mastoid, and medial ear canal were filled with contiguous soft tissue density material. MRI demonstrated an extensive intraosseous meningioma of the right petrous temporal bone with a large middle fossa soft tissue component displacing the inferior right temporal lobe. The tumor extended inferiorly through the floor of the middle cranial fossa to fill the middle ear, extend into the medial ear canal, and encase the distal internal carotid artery.

The patient underwent a combined middle fossa craniotomy, radical mastoidectomy, and decompression of the facial nerve within the fallopian canal. A lumbar drain was placed to facilitate brain relaxation and temporal lobe retraction. Tumor was found to fill the tympanic cavity, obliterate the tympanic membrane, dislodge the incus, and extend into the ear canal. The tumor was resected, and the ear canal was oversewn. A radical mastoidectomy was performed, and the facial nerve was identified and decompressed. Extensive bony resection of the middle fossa floor was performed with a diamond burr. The intracranial tumor was resected, with a small residual left encasing the distal carotid artery. Pathology was consistent with a WHO grade I meningioma. The patient was discharged with stable right-sided facial paralysis and complete hearing loss.

Three-month MRI demonstrated minimal residual meningioma encasing the distal extracranial carotid artery. Facial nerve function did not significantly improve, and the patient underwent gold weight placement in the right eyelid for lagophthalmos. She has received external whole beam radiation to the floor of the middle fossa and small residual extracranial tumor.

Conclusion: Middle fossa meningiomas should be included in the differential of EAC lesions and in those patients presenting with facial nerve weakness and conductive hearing loss. Multidisciplinary teams consisting of otology/otolaryngology, neurosurgery, and radiation oncology maximize patient care.

No conflict of interest has been declared by the author(s).