Neurofibromatosis/2: A genetic condition that usually causes acoustic neuromas to form on both hearing nerves. Acoustic neuromas (more properly called "vestibular schwanomas") are benign, usually slow growing tumors that grow on the covering of the acoustic nerves. They normally cause a high frequency hearing loss that progresses over time and can result in virtual deafness. The tumors can be surgically removed or treated with radiation.
NF2 is an extremely rare condition which is estimated to affects fewer than 1 in 40,000 people. Although the condition is genetic, about 50% of the cases are not inherited from one's parents, but are spontaneous. Although NF2 usually results in acoustic neuromas, most people with an acoustic neuroma only have one tumor and do not have NF2.
For more information checkout this Google Search.