vestibular schwannoma

a slow-growing benign tumour arising on one of the vestibular nerves. It is also known as an acoustic neuroma, but this is a misnomer as the tumour arises from Schwann cells rather than nerve cells and on a vestibular nerve rather than the cochlear (acoustic) nerve. Symptoms include hearing loss, tinnitus, and imbalance and there is an increased prevalence of the tumour in patients who have neurofibromatosis type II. Diagnosis is by MRI scan and treatment is not always required. In those cases where treatment is necessary, this may be by surgery, radiotherapy, or gamma knife.