The prevalence of vestibular schwannoma among patients treated as sudden sensorineural hearing loss

Objective To assess the prevalence of vestibular schwannoma (VS) in patients with sudden sensorineural hearing loss (SSNHL). Methods This is a retrospective chart review of 861 patients who were diagnosed with or treated for SSHNL between January 2008 and February 2017 at our department in a tertiary academic center. We retrospectively analyzed the medical charts and MRI findings of 499 patients who had undergone MRI. Results Fifteen (3.0%) of the 499 patients exhibited tumors at the cerebellopontine angle on the same side affected by SSNHL. In one patient, a tumor was incidentally detected in the contralateral ear. The 15 VS lesions were graded using the Koos acoustic neuroma grading system as follows: grade I (intracanalicular tumor), n = 8; grade II (up to 2 cm), n = 6; and grade III (up to 3 cm), n = 1. Koos grade IV tumors, which are large tumors that displace the trunk or cranial nerves, were not found. Conclusion The prevalence of VS in patients with SSNHL was 3.0% in the present study. Considering this high prevalence, clinicians should consider detailed examinations in addition to audiometry for patients with SSNHL.