Intralabyrinthine Schwannomas: Diagnosis, Management, and a New Classification System

Objective: To outline the diagnosis and management of intralabyrinthine schwannomas and to propose a new classification system to further define them. Study Design: Retrospective case review. Setting: Tertiary referral center at a university hospital. Patients: Twenty-eight patients seen at the institution with intralabyrinthine schwannomas between 1996 and 2002 were included in the study. Interventions: Diagnosis was made with magnetic resonance imaging in all but one case. Our ability to detect these tumors has been greatly enhanced by the introduction of high-resolution T2-weighted magnetic resonance imaging. Treatment options were observation with serial magnetic resonance imaging versus complete surgical removal via a translabyrinthine or transotic approach. Surgery was indicated for dizziness caused by the tumor or extralabyrinthine growth. Main Outcome Measures: Clinical features, audiology, radiology, and management outcomes were evaluated. Results: Eight patients have undergone successful surgery with removal of their tumors and resolution of symptoms. One patient chose to have stereotactic radiotherapy. Of the 20 patients who were managed with observation and serial magnetic resonance imaging, only 1 has shown significant growth requiring surgical removal. Conclusion: Intralabyrinthine schwannomas are uncommon tumors that mimic the clinical features of many other neurotologic conditions. A high index of suspicion and precise imaging are often required to detect these tumors. Surgical treatment is indicated for specific indications and will be needed in the minority of patients with this disorder. The classification system that we propose is helpful in both the diagnosis and the management of these tumors.