Vestibularlike facial nerve schwannoma

Abstract

Objectives: 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 over a 5-year period for tumors of the internal auditory canal extending or not into the cerebello-pontine angle (TICA), 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. 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 retrosigmoid approach. Unsuspected facial nerve schwannomas were found during surgery. Tumor removal was not performed. Postoperatively facial function was normal in 1 case and House and Brackman 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 staged tumors especially when the auditory and facial functions are normal.