NF2 is best managed at a specialty clinic with an initial screening and annual follow-up evaluations (more frequent if the disease is severe). Improved diagnostic technologies, such as magnetic resonance imaging (MRI), can reveal tumors of the vestibular nerve as small as a few millimeters in diameter. Vestibular schwannomas grow slowly, but they can grow large enough to engulf one of the eighth cranial nerves and cause brain stem compression and damage to surrounding cranial nerves. Surgical options depend on tumor size and the extent of hearing loss. There is no general agreement among doctors about when surgery should be performed or which surgical option is best. Individuals considering surgery should carefully weigh the risks and benefits of all options to determine which treatment is right for them. Surgery to remove the entire tumor while it’s still small might help preserve hearing. If hearing is lost during this surgery, but the auditory nerve is maintained, the surgical placement of a cochlear implant (a device placed in the inner ear, or cochlea, that processes electronic signals from sound waves to the auditory nerve) may be an option to improve hearing. As tumors grow larger, it becomes harder to surgically preserve hearing and the auditory nerve. The development of the penetrating auditory brain stem implant (a device that stimulates the hearing portions of the brain) can restore some hearing in individuals who have completely lost hearing and do not have an auditory nerve present. Surgery for other tumors associated with NF2 is aimed at controlling or relieving symptoms. Surgery also can correct cataracts and retinal abnormalities.
Because NF2 is so rare, few studies have been done to look at the natural progression of the disorder. The course of NF2 varies greatly among individuals, although inherited NF2 appears to run a similar course among affected family members. Generally, vestibular schwannomas grow slowly, and balance and hearing deteriorate over a period of years. A recent study suggests that an earlier age of onset and the presence of meningiomas are associated with greater mortality risk.
Signs of NF2 may be present in childhood but are so subtle that they can be overlooked, especially in children who don’t have a family history of the disorder. Typically, symptoms of NF2 are noticed between 18 and 22 years of age. The most frequent first symptom is hearing loss or ringing in the ears (tinnitus). Less often, the first visit to a doctor will be because of disturbances in balance, visual impairment (such as vision loss from cataracts), weakness in an arm or leg, seizures, or skin tumors.
- bilateral vestibular schwannomas; or
- a family history of NF2 (parent, sibling, or child) plus a unilateral vestibular schwannoma before age 30; or
- any two of the following:
- juvenile posterior subcapsular/lenticular opacity (cataract) or juvenile cortical cataract
Although individuals with NF2 may have schwannomas that resemble small, flesh-colored skin flaps, they rarely have the café-au-lait spots that are seen in NF1.
Individuals with NF2 are at risk for developing other types of nervous system tumors, such as ependymomas and gliomas (two tumor types that grow in the spinal cord) and meningiomas (tumors that grow along the protective layers surrounding the brain and spinal cord). Affected individuals may develop cataracts at an earlier age or changes in the retina that may affect vision. Individuals with NF2 may also develop problems with nerve function independent of tumors, usually symmetric numbness and weakness in the extremities, due to the development of a peripheral neuropathy.