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Acoustic Neuroma
What is an Acoustic Neuroma?
An acoustic neuroma is a benign (noncancerous), usually slow-growing brain tumor that develops from the balance and hearing nerves supplying the inner ear. It results from the overproduction of Schwann cells, which wrap around nerve fibers to help support and insulate the nerves. Each year about 1 in 100,000 people develops an acoustic neuroma, making it a rare condition. The tumor is also known as a vestibular schwannoma.
As the tumor grows it affects the nerves that control hearing and balance, causing hearing loss in one ear, tinnitus (ringing in the ear), and dizziness or loss of balance. The tumor may also interfere with the trigeminal nerve, causing facial numbness. Large acoustic neuromas may push against important structures in the brain, becoming life-threatening.
Unilateral acoustic neuromas affect one ear, and commonly occur in adults between the ages of 30 and 60.
Bilateral acoustic neuroma affects both ears and is caused by a rare genetic condition called neurofibromatosis type 2 (NF2). NF2 usually develops in teens and young adults.
Causes of Acoustic Neuroma
Research scientists now believe that unilateral and bilateral acoustic neuromas form following the loss of the function of a gene on chromosome 22. This gene produces a protein that controls the growth of Schwann cells, and when it malfunctions, Schwann cell growth is uncontrolled, resulting in a tumor. Patients who have NF2 have inherited the faulty gene on chromosome 22.
Early Signs of Acoustic Neuroma and Diagnosis
Unilateral (one-sided) loss of hearing that worsens gradually, tinnitus, and dizziness or loss of balance are early signs of acoustic neuroma. Because symptoms may be subtle early in the growth of the tumor, detection can be difficult. Also, many problems of the middle and inner ear have the same symptoms. Other symptoms of acoustic neuroma are a feeling of fullness in the affected ear, headache, and facial numbness or tingling on the affected side.
If you have these symptoms, your doctor will recommend a thorough ear examination, hearing and balance testing, and neurological exams of your vision, muscle strength, and reflexes. MRI scans are important for accurate diagnosis and to determine the location and size of the tumor. They also help surgeons plan for microsurgical removal.
Treatment
Doctors at UTHealth Houston Neurosciences are committed to providing you and your family with compassionate care and the most advanced treatments.
There are three options for treating acoustic neuroma: surgical removal, radiation, and observation. Gamma Knife® radiosurgery may also be used to reduce the size or limit the growth of the tumor. If you have a small tumor that is not growing, your physician team may recommend watchful waiting.