Spontaneous Vestibular Schwannoma Regression: A Case-Control Study

<jats:sec> <jats:title>Objective:</jats:title> <jats:p>To explore the nature of spontaneously regressing vestibular schwannomas (VS) and identify possible predictive factors for such behavior.</jats:p> </jats:sec> <jats:sec> <jats:title>Study Design:</jats:title> <jats:p>Retrospective case control study.</jats:p> </jats:sec> <jats:sec> <jats:title>Setting:</jats:title> <jats:p>Tertiary referral center, university teaching hospital.</jats:p> </jats:sec> <jats:sec> <jats:title>Patients:</jats:title> <jats:p>Patients with sporadic VS demonstrating spontaneous regression compared with a control group of patients with growing VS.</jats:p> </jats:sec> <jats:sec> <jats:title>Interventions:</jats:title> <jats:p>Review of serial magnetic resonance imaging of the internal auditory meatus (MRI IAM) and case notes and direct comparison of possible related factors between the two groups using univariate analysis.</jats:p> </jats:sec> <jats:sec> <jats:title>Main Outcome Measures:</jats:title> <jats:p>Presenting symptoms, VS size and consistency, patients’ age and sex, tumor laterality and location, and the neutrophil-to-lymphocyte ratio between the two groups.</jats:p> </jats:sec> <jats:sec> <jats:title>Results:</jats:title> <jats:p>Of the 540 patients on the database 28 (5.2%) showed spontaneous regression with a mean follow-up of 122 months. Mean absolute and relative regression was 3.9 mm and 25.7%, respectively. 60% of tumors showed gradual regression while 25% showed growth followed by regression. Regressing VS had a significantly larger size than the control group; while the regressing tumors were located further from the fundus than the control group. The remaining examined factors did not reach a statistical level of significance.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusion:</jats:title> <jats:p>This is, to our knowledge, the first study comparing a cohort of regressing tumors with a control group of growing VS. The finding that the location of tumors around the porous, is more common in regressing VS has implications for patients’ counselling.</jats:p> </jats:sec>