Two Cases of Intratemporal Facial Nerve Neurilemmomas

Abstract

The patients with neurilemmomas of the facial nerve within the temporal bone were treated. Although most of cases of the facial nerve neurilemmoma in the temporal bone present with a facial palsy, a few cases have normal facial nerve function and are especially difficult to diagnose preoperatively because of few symptoms. Case 1, a 31-year-old man, developed progressive left facial palsy with protrusion of the posterior wall of the external auditory meatus over a five-month period. Case 2, a 64-year-old man, complained of only fullness and tinnitus of the right ear without any facial nerve symptoms. Polytomography of the temporal bone demonstrated no abnormal findings in both cases. However, computed tomography revealed a soft-tissue density area in the left mastoid cavity with destruction of the posterior wall of the external auditory meatus in case 1. A similar soft-tissue density mass was found in the right tympanic cavity in case 2, suggesting the presence of the tumor in the temporal bone. At operation, the tumors were found to originate from the vertical portion of the facial nerve in both cases. It was assumed that normally existing dehiscences of fallopian canal might account for why some patients have normal facial nerve function.