Malignant Peripheral Nerve Sheath Tumor of the Intratemporal Facial Nerve: A First Case Report and Review of the Literature

Objective: To report a novel case of an intratemporal malignant peripheral nerve sheath tumor (MPNST) arising from the mastoid segment of the facial nerve and a review of the relative literature.

Design: Case report and review of the relevant literature.

Setting: A large public county hospital and level-1 trauma center.

Participants: A 54-year-old female with a history of stage-III cervical carcinoma presenting with otorrhea, facial palsy, and an external auditory canal mass.

Main Outcome Measures: Description of clinical case presentation, diagnosis, and treatment of MPNST of the intratemporal facial nerve. Review of the existing peer-reviewed literature for prior similar cases and treatment strategies.

Results: Biopsy of the mass showed MPNST. The patient underwent lateral temporal bone resection, facial nerve decompression and sacrifice, dissection of the jugular foramen, total auriculectomy, total parotidectomy, selective neck dissection and microvascular free flap reconstruction. Tumor was noted to be filling the mastoid cavity confluent with the mastoid segment of the facial nerve with extension to the jugular bulb and jugular foramen. Pathology results confirmed MPNST. Ipsilateral neck dissection revealed no existing cervical metastases. After a short inpatient stay, the patient recovered well and underwent adjuvant chemoradiation. At most recent follow up, there appears to be no evidence of malignancy. Review of the literature was performed using Medline and Google Scholar. There are few previous reports of MPNST involving the lateral skull base and none reporting primary MPNST of the intratemporal facial nerve.

Conclusions: MPNST is a rare entity within the head and neck with limited reports in the literature of involvement of the lateral skull base. This is the first reported case of a primary MPNST arising from the intratemporal facial nerve.