Growing vestibular schwannomas: what happens next?

To determine the subsequent growth patterns in vestibular schwannomas shown to be growing on serial imaging.

Retrospective review.

Tertiary academic referral center.

Patients with tumors that demonstrated growth of greater than 1 mm/yr between 2 consecutive scans (magnetic resonance or computed tomography) and had at least 1 follow-up scan were included. Patients with neurofibromatosis were excluded.

Review of radiographic images (magnetic resonance imaging scans) or neuroradiologists' reports when the images were unavailable.

Maximum dimension along the axis of the internal auditory canal was measured for intracanalicular tumors, whereas for extracanalicular tumors, maximal dimension along any orientation was used. A significant difference in dimension was defined to be greater than 1 mm/yr, positive or negative.

Thirty-six patients were included in the study; 47% were women and with an average age of 60.2 years. The average follow-up period after growth was identified was 2.1 years. Of the growing tumors, 63.9% continued to grow, 30.6% stayed the same size, and 5.6% regressed in size.

Most vestibular schwannomas identified to be growing are likely to continue to grow on subsequent serial imaging. These results are useful in clinical decision making and counseling patients with growing vestibular schwannomas.