Is location more determining than WHO grade for long-term clinical outcome in patients with meningioma in the first two decades of life?

To identify factors for tumor relapse and poor outcome in patients with meningiomas in the first two decades of life. All patients ≤ 21 years of age who underwent resection of a meningioma at the department of neurosurgery, Medical University of Vienna between 1989 and 2022 were included in this retrospective study. Clinical and radiological data were extracted from the medical records. Outcome and tumor relapse were analyzed for tumor location, histological findings and extent of resection. In this study 18 patients were included, 6 meningiomas were located in the skull base, 5 in the convexity and 7 in other locations including intraventricular and spine (2 patients each), falx, intraparenchymal and optic nerve sheath. Most frequent symptoms were seizures and cranial nerve palsy. In total 56% of the meningiomas were World Health organization (WHO) grade 1, 39% grade 2 and 5% grade 3. Gross total resection was achieved in 67%. The overall relapse rate was 61% and 50% underwent repeat surgery. All patients with convexity meningiomas became seizure free and had a favorable outcome. Relapse and clinical outcome were independent of WHO grade among the whole cohort but the outcome significantly depended on the WHO grade when patients with skull base meningiomas were analyzed as a subgroup. The relapse rate was significantly higher in cases of skull base location (100% vs. 42%, p = 0.038) and after subtotal resection (100% vs. 42%, p = 0.038). Clinical outcome was also significantly worse and the rate of complications was higher in patients with skull base meningiomas. Patients with convexity meningiomas in the first two decades of life have a good outcome due to high chance of gross total resection. Patients with skull base meningioma are at high risk of relapse and poor outcome, particularly those with WHO grades 2 and 3. Subtotal resection in patients with skull base location is probably the main reason for this difference.