MRI monitoring of small and medium-sized vestibular schwannomas: predictors of growth.

Vestibular schwannomas are among the most common intracranial tumours. Their growth is difficult to predict. To study the evolution of small and medium-sized vestibular schwannomas (VSs) and identify factors predictive of growth. This was a retrospective longitudinal study at a tertiary referral centre from January 2011 to January 2018. The inclusion criteria were radiological diagnosis of sporadic unilateral VS of stage I or II. Radiological and clinical data were analysed descriptively and by multivariate logistic regression to identify factors predictive of growth. A total of 1105 cases were discussed in multidisciplinary meetings and 336 patients were included with a mean age of 57.8 years and a mean follow-up time of 24 months. Around two thirds of these patients (62.8%) had non-progressive tumours. Factors identified as predictive of VS growth were the size at diagnosis (OR = 2.622, 95% CI, 1.50-4.66;  = .001) and internal auditory canal filling (OR = 7.672; 95% CI, 4.52-13.43;  < .001). Monitoring is the primary treatment modality for small or medium-sized VSs. As reported here for the first time, internal auditory canal filling is significantly associated with VS growth.