Cystic Vestibular Schwannomas have Similar Surgical Outcomes and Recurrence Rates as Solid Vestibular Schwannomas

Introduction: Vestibular Schwannomas are relatively common benign tumors and make up the majority of cerebellopontine angle masses. Cystic vestibular schwannomas (CVS) represent a subtype that are commonly thought to behave more aggressively than solid vestibular schwannomas (SVS) although their comparative outcome has not been well studied.

Methods: An institutional pathological database was queried for all patients harboring vestibular schwannomas between January 2009 and January 2014. The medical records and imaging of patients meeting criteria were retrospectively reviewed and statistical analysis was performed to study the differences in clinical outcomes and tumor progression or recurrence between solid and cystic vestibular schwannomas.

Results: CVS accounted for 25% of 112 total tumors. On multivariate analysis, the only significant difference in cystic tumors was larger side. Cystic tumors had a significantly higher postoperative facial nerve deficit on univariate analysis. However, when adjusted for tumor size on multivariate analysis, there was no significant difference. Cystic tumors did have a significantly higher MIB 1 index, but there was no difference in progression or recurrence for these lesions after surgical resection.

Conclusion: In our series CVS were significantly larger than solid tumors. When adjusted for this difference in size, there was no significant difference in facial nerve outcome, progression, or recurrence rate. Due to their unpredictable growth pattern and response to radiation, microsurgical resection is the optimal treatment for these tumors. Contrary to common belief, our data does not support that these tumors behave more aggressively or are associated with increased postoperative facial nerve deficit.