Vestibular-like facial nerve schwannoma

Abstract

Problem: Apparent vestibular schwannoma (VS) may be in fact primary facial nerve schwannoma (PFNS). The purpose of the present study was to evaluate the prevalence as well as the management of PFNS presenting as VS. Methods: Based on an inception cohort of 146 patients operated in our institution over a 5-year period for tumors of the internal auditory canal (extending into the cerebello-pontine angle [TICA] or not), the prevalence and management of tumors originating from the facial nerve were retrospectively reviewed. A review of the literature included an extensive MEDLINE search of the literature and careful inspection of the bibliography of each article. Articles pertaining to facial nerve schwannomas were reviewed to identify cases of vestibular-like facial (V-LF) nerve schwannoma. Results: Two cases of tumors were finally diagnosed as PFNS. Clinical and radiological evaluations were typical of a vestibular schwannoma. Auditory and facial functions were normal in each case. Both patients had stage II tumor and were operated through the retrosigmoid approach. Unsuspected facial nerve schwannomas were found during surgery. Tumor removal was not performed. Postoperatively facial function was normal in one case and House-Brackmann grade II in the other case. These 2 cases represented 1.4% prevalence, which is within the ranges reported in the literature. The review of the literature of V-LF nerve schwannoma demonstrated that the postoperative functional facial outcome usually worsened when the tumor was resected. Conclusion: Although low, the prevalence of V-LF nerve schwannoma might argue for the conservative management of early-stage tumors, especially when the auditory and facial functions are normal. Significance: The conservative management of early-stage tumors presenting as vestibular schwannoma is recommended in order to counsel the patient regarding the possibility of V-LF nerve schwannoma and to prolong normal facial function. Support: No support