High-Grade Glioma is not a Feature of Neurofibromatosis Type 2 in the Unirradiated Patient
The Manchester criteria for neurofibromatosis type 2 (NF2) include a range of tumors, and gliomas were incorporated in the original description. The gliomas are now widely accepted to be predominantly spinal cord ependymomas. To determine whether these gliomas include any cases of malignant glioma (WHO grade III and IV) through a database review. The prospective database consists of 1253 patients with NF2. 1009 are known to be alive at last follow-up. There was a single case of glioblastoma multiforme (GBM; World Health Organization grade IV) in the series and no WHO grade III gliomas. The GBM was in a patient who had previously undergone stereotactic radiosurgery for a vestibular schwannoma. High-grade gliomas are not a feature of NF2 in the unirradiated patient and should be excluded from the diagnostic criteria.