Meningiomas and neurofibromatosis.

Neurofibromatosis type 2 (NF2) is a rare genetic disorder predisposing to multiple benign tumors of the nervous system. Meningiomas occur in about half of NF2 patients, and are often multiple. Patients harboring seemingly isolated multiple meningiomas should be investigated to diagnose NF2 by careful familial history collection, detailed clinical examination (skin lesions and slit lamp examination of the lens), audiovestibular testing, and fine cranio-spinal Magnetic Resonance Imaging. Somatic mosaicism is frequent in NF2 and may explain a mild phenotype as, e.g. isolated multiple meningiomas. Neurofibromatosis type 1 is not associated with an increased risk of meningioma. Whether meningiomas are part of the schwannomatosis tumor phenotype or not remains debated. Meningiomas in NF2 patients are associated with a higher risk of mortality, and their treatment is challenging, but data about natural history of meningiomas in NF2 patients in the literature are sparse. Thus, knowledge of tumor behavior is essential in slow growing tumors like meningiomas, to balance the risk of treatment against the natural history of the disease, and to evaluate the efficiency of alternative therapeutics (radiation therapy or new drugs).