Objective: To evaluate the prevalence as well as the management of primary facial nerve schwannoma (PFNS) presenting as vestibular schwannoma.
Methods: A retrospective review was carried out on 146 patients referred to and operated upon in our institution over a 5-year period for tumors of the internal auditory canal extending or not into the cerebello-pontine angle (TICA). A review of the literature included an extensive MEDLINE search of the literature since 1966 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. Facial function was normal in each case. Unsuspected facial nerve schwannomas were found during surgery. Tumor removal was not performed. Postoperatively House and Brackmann (HB) facial function was normal in one case and grade II in the other case. These two cases represented a 1.4% prevalence, which is within the limits reported in the literature. Among V-LF nerve schwannomas reported in the literature, the postoperative functional facial outcome usually worsened when the tumor was resected.
Conclusion: The prevalence of V-LF nerve schwannoma has been reported in the two last decades owing to the development of modern imaging. The conservative management of early staged 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.