Acoustic neuroma (or vestibular schwannoma) is a benign slow-growing tumor that develops on the main (vestibular) nerve leading from the inner ear to the brain. Branches of this nerve directly influence balance and hearing. The tumour usually arises from the Schwann cells covering this nerve and grows slowly or not at all. Rarely, it may grow rapidly and become large enough to press against the brain and interfere with vital functions.
It accounts for about 6% of intracranial tumors and is categorized into two types: sporadic (usually unilateral localization) and type 2 neurofibromatsis (usually bilateral). It most commonly occurs between 40 and 60 year old adults.
Signs and symptoms of acoustic neuroma
Signs and symptoms are often subtle and may take many years to develop. They usually arise from the tumor’s effects on the hearing and balance nerves. Thus, gradual hearing loss and tinnitus (ringing of ears) of the affected ear and dizziness or loss of balance. Pressure from the tumor on adjacent nerves controlling facial muscles and sensation (facial and trigeminal nerves), nearby blood vessels, or brain structures may also cause problems such as facial numbness and very rarely, weakness or loss of muscle movement.
Acoustic Neuroma
Diagnosis is often difficult in the early stages due to the subtle signs and symptoms. A thorough medical examination including an audiometry will be performed by the ENT specialist and further imaging will be ordered. Magnetic resonance imaging (MRI) is the preferred imaging test to confirm the presence of acoustic neuroma and can detect tumors as small as 1 to 2 millimeters in diameter.
Various treatment modalities have been suggested for the treatment of acoustic neurinoma, such as monitoring, surgical removal, stereostatic radiation surgery, and even classical radiation therapy. Each of these methods have their advantages and disadvantages.