From sound to silence: a case study of neurofibromatosis type II

Neurofibromatosis is a disease that occurs in both males and females of all races and ethnic groups. It is inherited as a dominant disorder but can also occur as a new mutation. Neurofibromatosis was formerly considered a single disorder with at least two variations. However, it is currently known to be two distinct entities, Neurofibromatosis Type I (NF I), which is caused by a defective gene localized to chromosome 17 and Neurofibromatosis Type II (NF II), which is caused by a defective gene localized to chromosome 22. NF II is the less common form, affecting 1 in 40,000 persons. The distinguishing clinical feature of NF II is the presence of bilateral vestibular schwannomas. This is a case of a 15-year-old boy who presented with a mild hearing loss in the left ear and a nine month history of prominent hearing loss in the right ear. Brain magnetic resonance imaging (MRI) showed bilateral enhancing lesions in the cerebellopontine angle which extend into the internal auditory canal, consistent with vestibular schwannoma. He has no family history of Neurofibromatosis.