Facial nerve schwannomas: different manifestations and outcomes

The purpose of this study was to provide data on the different clinical presentations of facial nerve schwannoma, the appropriate planning for the management of schwannoma of various origins, and the predictive outcomes of surgical management.

A retrospective study was conducted in a tertiary referral hospital. We reviewed 8 consecutive cases of facial nerve schwannoma diagnosed and managed between 1993 and 2001.

Facial nerve schwannomas originated in the internal auditory canal (IAC) (2 cases), parotid gland (2 cases), intratemporal portion (3 cases), and stylomastoid foramen (1 case). Tumor of the stylomastoid foramen presented as an intra- and extratemporal mass. The initial presenting symptom of the 8 patients was facial nerve paralysis in 4 patients, hearing loss in 2, facial numbness in 1, and an infra-auricular mass in 1. Facial palsy occurred in 7 patients during the course of the disease. One patient with a mass in the parotid gland did not show facial palsy up to 1 year after presentation of the initial symptom (facial numbness). Facial nerve paralysis was most severe in intratemporal tumors and less severe in parotid tumors. The patients with IAC suffered from hearing loss and intermittent vertigo and showed decreased vestibular function. The patients with intratemporal tumors also complained of hearing loss. The tumors were completely removed by superficial parotidectomy for parotid tumors; the translabyrinthine approach for 1 IAC tumor and 1 intratemporal tumor; the middle fossa approach for the other IAC tumor; the transmastoid approach for mastoid tumors; and the infratemporal fossa approach for intratemporal and extratemporal tumors. End-to-end cable grafts for the facial nerve were performed in 5 out of 8 cases. In 2 cases, the facial nerve was preserved after the resection of the mass. One case showed complete loss of the peripheral branch of the facial nerve.

Facial nerve schwannoma can present in various ways. By examining the site of origin and the presenting symptoms and signs, we were able to diagnose facial nerve schwannoma preoperatively. According to the operative management of the facial nerve, the postoperative outcome of facial function could be estimated. Our finding could be pivotal in the management of the facial nerve schwannoma.