Age at Onset and Presenting Symptoms of Neurofibromatosis Type 2 as Prognostic Factors for Clinical Course of Vestibular Schwannomas
The presenting symptoms of the tumor suppressor gene syndrome neurofibromatosis type 2 (NF2) are often non-specific and unrelated to the disease hallmark bilateral vestibular schwannomas (VS). However, age at onset and presenting symptoms may have predictive values for the clinical course of VS. In this retrospective single-center study, we addressed this issue by reviewing 106 patients with 194 VS. Presenting symptoms attributable to VS commonly occur in 87% of adults and 31% of children. Age at onset significantly correlates with tumor volumes at presentation (p = 0.034). In addition, age at onset significantly correlates with pure-tone average (p = 0.0001), speech discrimination scores (p = 0.001), age at beginning of hearing loss (p = 0.0001), age at deafness (p = 0.0001), and age at first surgery (p = 0.0001). Patients presenting with VS related symptoms had significantly (p < 0.05) worse hearing values at presentation and after surgery. These patients also exhibited higher growth rates and tumor volumes compared to patients with non-VS related presenting symptoms, but this difference did not reach the significance level of p < 0.05. Due to the late appearance of these symptoms, the time of beginning hearing loss, surgery and deafness is significantly delayed (p < 0.05) compared to patients not presenting with VS. In summary, age at onset and type of presenting symptom provide excellent prognostic parameters for predicting VS- and hearing-related clinical course.