[Neurofibromatosis type 2].

Type 2 neurofibromatosis (NF2) is an invalidating, inherited, dominant, autosomal disease. It is commonly confused with type 1 neurofibromatosis, although the two disorders are different. All subjects who inherit a mutated NF2 gene will develop the disease, which is characterised by the growth of schwannomas, generally affecting the vestibular nerve bilaterally, as well as meningiomas and other benign central nervous system tumours, before their third decade of life. It is currently possible to identify the NF2 mutation in most affected families. Up to about 20% of NF2 patients with no family history, apparently sporadic cases, are actually individuals with mosaicism for this mutation. Much of the morbidity from these tumours results from their treatment, which is primarily surgical. Small vestibular schwannomas can often be completely resected with preservation of both hearing and facial function. In case of large tumours it is possible to place a cochlear or brain stem implant during the schwannoma surgery. Age at diagnosis, the presence of intracranial meningiomas, and whether the patient was treated at a specialty centre or not, have been cited as the strongest prognostic factors.