Incidental findings of a Vestibular Schwannoma on Brain MRI.

Brain magnetic resonance imaging (MRI) is the gold standard for diagnosing a vestibular schwannoma (VS). The prevalence of VS ranges from 0.02-2.4%; the incidence is 20 per million per year. This case report describes two cases of VS identified on brain MRIs that were not related to the purpose of the MRI examination. A literature search was performed to find existing audiometric-based protocols for guiding MRI referrals. Asymmetric sensorineural hearing loss appeared to be the most important indication for excluding VS. However, no consensus was found on the significance of asymmetry or on the severity required to exclude VS. In light of the current absence of a reliable audiometric-based protocol for MRI referral, it seems reasonable to refer every patient with audiovestibular symptoms for a brain MRI, despite the view that the low number of incidental findings may not justify the additional cost.