Long-term follow-up results of facial nerve schwannoma with good facial nerve function: a multicenter study.

Purpose: Facial nerve schwannomas (FNSs) are rare intracranial tumors, and the optimal management of these tumors remains unclear. We investigated the long-term follow-up results of FNS with good facial nerve function.

Methods: At nine medical centers in the Korean Facial Nerve Study Group, 43 patients undergoing observation periods longer than 12 months for FNS with good facial nerve function (House-Brackmann grade ≤ II) were enrolled, and clinical and radiographic data were obtained for these cases.

Results: The mean follow-up period was 63 months. In the majority of cases, tumors involved multiple segments (81.4%) and only eight cases were confined to a single site. There were no cases where the tumor was confined to the extratemporal region. Tumor size increased slightly, with an average estimated change of 0.48 mm/year. Twenty (46.5%) of 43 patients showed no change in tumor size. Seven patients (16.3%) showed worsening House-Brackmann (H-B) grade, of which two patients deteriorated from H-B grade I to II, four worsened to grade III, and one deteriorated to grade IV. The remaining 36 patients (83.7%) showed no change in facial nerve function. There was no difference in H-B grade according to tumor size at the time of diagnosis or change in tumor size.

Conclusion: We conducted a large-scale observational study of FNS with good facial nerve function. Our study showed that many patients maintained facial nerve function during long-term follow-up. Conservative management with regular examination and imaging can be an appropriate option for managing FNS with good facial nerve function.