FREDERIC B.ASKINMDWILLIAM H.WESTRAMD
Neurilemmomas, or schwannomas, are fairly common tumors of the head and neck, with tumors of the eighth nerve predominating. While the estimated incidence of eighth nerve schwannoma is 0.8 to 2.5 per 100 000,1,2 schwannomas of the facial nerve are less commonly diagnosed, with the intratemporal lesions being more familiar to otolaryngologists, as they present early with progressive facial paralysis or hearing loss.3,4 Tumors of the facial nerve in the cerebellopontine angle or internal auditory canal may also present with hearing loss, tinnitus, and vestibular symptoms.4,5 In a study of 600 temporal bones, asymptomatic facial neurilemmomas were found in 5 (0.83%).6 Patients with extratemporal facial schwannomas present with larger tumors, reporting an asymptomatic parotid mass, pain, gradual facial weakness, or facial motor abnormalities. The incidence of extratemporal facial schwannomas is unknown, but is reported to be as high as 1.3% of all parotid tumor specimens.3,7,8 Conley and Selfe9 estimated that schwannomas accounted for 15% of all "occult" parotid neoplasms, in which facial paralysis occurred despite the absence of a clinically diagnosed tumor. With modern computed tomography and high-resolution magnetic resonance imaging, however, it is possible to diagnose most tumors that can cause facial paralysis before surgical exploration.
Diagnosis Pathology Quiz Case 1. Arch Otolaryngol Head Neck Surg. 2002;128(11):1328. doi: