Cystic versus Non-Cystic Large Vestibular Schwannomas: Presentation and Outcome, a Matched Controlled Series

Objective: Cystic vestibular schwannomas (CVSs) present different clinical, radiological, and treatment-outcomes from their solid counterparts. We reviewed our database to identify CVSs and compare them to matched controls.

Methods: The skull base database of 431 vestibular schwannomas at our institution was reviewed to identify all patients presenting with CVS. Each CVS was matched with non-cystic VS (NSVS). Data were collected on both groups from imaging and from review of the health records. The two groups were compared in terms of demographic features; presenting symptoms and signs; tumor characteristics; and treatment outcomes in terms of hearing preservation, facial function preservation, and complications. Tumor and cyst volumes were calculated on imaging using Kodak Carestream software and the Broderick method, (A × B × C)/2. The means were compared using Student's paired t-test.

Results: Twenty-six patients were included in this study, 13 of which were CVS and 13 NCVS. The cystic tumor group were slightly older than the control group (66.5 vs. 57.2 years; P = 0.053). Overall tumor volumes were similar between the two groups (4.4 vs. 5.5 c cm; P = 0.13). At presentation, there was no significant difference hearing loss, tinnitus and headaches. However, CVS had had longer duration of hearing loss (48 vs. 18 months; P < 0.01) and facial pain (23.1% vs. 0%; P < 0.05) compared with their counterparts. The mean volume of VS in each group was comparable (6.1 vs. 5.5 c cm). There was no difference in follow-up (4.8 vs. 5.3 years). Following retrosigmoid surgical excision, 22.2% of CVS had normal facial function compared with 36.4% in NCVS. HB 2 and 3 was 66.6% in CVS compared with 27.3% in NCVS, 44.4% of CVS had serviceable hearing postoperatively (46.2% preoperatively) compared with 18.2% of NCVS (38.5% preoperatively), and 22.2% of CVS had presented with hydrocephalus compared with 11.1% of NCVS. There was one VPS in the NCVS and one CSF and infection in each group.

Conclusions: Patients presenting with cystic vestibular schwannoma had presented with significantly longer duration of hearing loss and were more likely to present with facial pain. Though more patients with CVS had better facial and hearing preservation, this was not statistically significant.