Background: Reported epidemiologic data surrounding vestibular schwannoma (VS) are controversial.
Temporal bone studies have suggested that asymptomatic, incidentally diagnosed VS
affects up to 2.4% (or 2,400 per 100,000 persons) of the population,[1] whereas magnetic resonance imaging (MRI) studies have reported VS to affect 0.0108%
(or 11 cases per 100,000 persons).[2] Moreover, existing population-based data seem to consistently underestimate the
prevalence of VS.[3]
Objective: For these reasons, the current study was conceived to determine the prevalence of
sporadic VS in Olmsted County, Minnesota, in an attempt to reconcile temporal bone,
radiologic, and population-based reports regarding VS.
Patients: All persons living in Olmsted County, Minnesota, on January 1, 2017, with a confirmed
diagnosis of VS identified using the Rochester Epidemiology Project (REP) medical
records-linkage system.
Main Outcome Measures: Prevalence of all sporadic VS and asymptomatic, incidentally diagnosed sporadic VS.
Results: Among the more than 159,000 persons living in Olmsted County on January 1, 2017,
we identified 67 living with VS, resulting in a point prevalence of 42.0 per 100,000
persons ([Table 1]). The prevalence of VS was higher in older persons, reaching 212.4 per 100,000 in
those aged 70 years and older ([Fig. 1]). The overall prevalence of asymptomatic, incidentally diagnosed VS was 7.5 per
100,000 persons, and 10.3 when restricted to those aged 20 years and older.
Conclusion: Using the unique infrastructure of the REP, the current study shows that sporadic
VS affects over 40 people per 100,000, with prevalence reaching over 1 in every 500
persons aged 70 years and older. The prevalence of asymptomatic, incidentally diagnosed
sporadic VS closely compares to past MRI studies ([Table 2]). Yet, the estimates of prevalence from temporal bone studies remain at least one
order of magnitude greater than the current population-based study and past radiologic
research. In this way, the current study demonstrates similarities between available
population-based prevalence data and previous MRI studies while further substantiating
the speculation that temporal bone studies systematically overestimate the prevalence
of VS. Lastly, taken together, the currently available data suggest that asymptomatic,
incidentally diagnosed VS likely affects between 5 and 20 people per 100,000 persons.
