Acoustic Neuroma

What Is Acoustic Neuroma?

Acoustic neuroma is an uncommon, noncancerous (benign) and usually slow­growing tumor that develops on the main nerve leading from your inner ear to your brain. Because branches of this nerve directly influence your balance and hearing, pressure from an acoustic neuroma can cause hearing loss, ringing in your ear and unsteadiness

Acoustic Neuroma: Types & Stages

The stages of acoustic neuroma (vestibular schwannoma) may be thought of as 1) a period of development; 2) diagnosis; and 3) treatment or management.

The development stage of acoustic neuroma varies depending on the type of schwannoma. In the case of unilateral acoustic neuroma, affecting only one ear, the tumor grows very slowly and symptoms often do not appear until age 30 and as late as age 60. In the case of bilateral acoustic neuroma, the cause is hereditary and the condition exists at birth, although symptoms may not appear until the teen years.

For the patient, the diagnosis stage of acoustic neuroma begins with the early symptoms of hearing loss, ringing in the ears (tinnitus), or vertigo, continuing with tests to isolate the cause.

The next stage of acoustic neuroma for the patient is determined with the doctor based on the results of tests. The strategy may involve surgery, radiation, or even monitoring

Acoustic Neuroma – Detection & Treatment

Diagnosing Acoustic Neuromas

Acoustic neuromas begin is tiny growths that develop into larger tumors, and thanks to advances in diagnostic technology, it’s now possible to detect them even when they’re only a few millimeters across. Generally, an acoustic neuroma is first detected during a routine auditory test, which measures hearing loss. If one ear suffers hearing loss and the other is normal, this is a warning sign for an acoustic neuroma and should be investigated with an MRI.

Optionally, a doctor may choose to use an auditory brainstem response test (also called ABR, BAER, or BSER), which measures the electrical connectivity of the brainstem to the inner ear. The presence of an acoustic neuroma can interfere with these electrical channels even before hearing is affected, so an abnormal result in an ABR may signify the presence of an acoustic neuroma. If an abnormal result is found, the patient should undergo an MRI. If an MRI isn’t feasible, a computerized tomography (CT) scan can be used as a substitute.

Symptoms of Acoustic Neuroma

Early-stage symptoms of acoustic neuroma are easy to mistake for other conditions or overlook completely. Common early symptoms include loss of hearing in one ear, ringing in the ear (tinnitus), or a feeling of fullness in the ear. Often, these symptoms are attributed to aging or noise exposure in early life, which delays the diagnosis of many acoustic neuromas.

As the tumor grows, it presses on the balance portion of the eighth nerve, which can cause balance problems, unsteadiness, or vertigo (feeling like the room is spinning) in patients. Very large tumors can press on the trigeminal nerve, which causes numbness or tingling in the face, or even on the brain, which causes headaches. These more advanced symptoms can come with potentially fatal complications, so treatment should be sought immediately in these cases.

Treatment Options for Acoustic Neuroma

Acoustic neuroma vary greatly in size and severity, so different treatment options are appropriate for different patients. The treatment you and your doctor choose will depend on the size, placement, and growth rate of the acoustic neuroma, but there are three major options available.


In some cases, the first step of treatment is simply to watch the tumor and wait. This is often the case in older patients with a small acoustic neuroma. Acoustic neuromas are ultimately benign, and in many older patients the tumor won’t grow and thus won’t require treatment. Typically, this treatment course requires periodic MRIs to track the size of the tumor.

Microsurgical Removal

If the tumor does require active treatment, surgical removal is an option. There are three degrees of surgical removal, each appropriate in certain situations:

  1. Subtotal Removal: If removing the tumor would threaten the life or neurological function of the patient, the doctor may opt to remove only a portion of the tumor. While this treatment can eliminate problems, it does leave open the possibility of regrowth, so regular MRI studies are important to track the tumor.
  2. Near Total Removal: In cases where complete removal would potentially damage the facial nerve, a physician may opt for near total removal. In this method, almost the entire tumor is removed, leaving only tissue closest to key nerves. Usually, the remaining pieces of the tumor account for only 1% of its mass and the risk of regrowth is minimal, but periodic MRIs are still recommended to track the tumor.
  3. Total Removal: In many cases, the entire tumor can be surgically removed. Modern microsurgical tools and techniques have greatly reduced the risks of tumor removal, and both the facial nerve and hearing function are electrically monitored in real time during the surgery, helping the surgeon avoid damaging these important structures. In most cases, this is a routine procedure that safely and effectively treats the acoustic neuroma.

Radiation Therapy

Outside of physical surgery, radiation therapy offers a highly effective treatment for acoustic neuroma. At Orange County CyberKnife, we’re proud to use one of the most advanced, effective radiation treatment systems in the world, and our team of experienced radiation oncologists, medical physicists, and other treatment professionals have helped countless patients through radiosurgery. In most cases, both hearing and facial nerve function are completely preserved and the tumor is eliminated in full.

CyberKnife is a revolutionary radiation therapy system that combines some of the most advanced technologies in cancer treatment to create a highly effective, extremely convenient treatment method for cancer and other growths. CyberKnife delivers a precisely calibrated, finely-measured dose of energy – the same kind found in visible light – to the tumor, and the rotating robotic arm of CyberKnife allows it to deliver radiation on all sides of the tumor. This dose of energy damages the cells of the tumor and stops them from replicating. Once the remaining cells of the tumor die, they’re eliminated naturally by the body.

CyberKnife treatments are usually given in small doses called fractions on a near-daily basis over the course of about 6 weeks. Follow up to CyberKnife treatment requires an MRI scan and an audiogram 6 months after the procedure, 1 year after the procedure, and annually for the next several years.

Contact Your Orange County Cancer Treatment Center

While many acoustic neuromas are benign, they can cause serious, sometimes life-threatening side effects and complications as they grow. At OC CyberKnife, we’re committed to helping our patients overcome their health conditions and lead a full, happy life. If you or a loved one has recently been diagnosed with cancer, acoustic neuroma, or any other condition, we are here to help you. Feel free to call us at 714.962.7100 with any questions or reach out to us at our contact page to schedule an appointment at our Orange County, CA cancer treatment facility.

Acoustic Neuroma: FAQs

Answer :

An acoustic neuroma, known as a vestibular schwannoma, is a benign (non­cancerous) growth that arises on the eighth cranial nerve leading from the brain to the inner ear.

Answer :

Although there is an heritable condition called Neurofibromatosis Type 2 (NF2) which can lead to acoustic neuroma formation in some people, most acoustic neuromas occur spontaneously without any evidence of family history (95%).

Answer :

Most recent publications suggest that the incidence of acoustic neuromas is rising. This is because of advances in MRI scanning both on incidental scans and for patients experiencing symptoms. It is estimated that the instances of acoustic neuroma are 3.5 in every 100,000 and more than 5,000 diagnosed annually in the US. Most acoustic

Answer :

There is a growing body of evidence that sporadic defects in tumor suppressor genes may give rise to these tumors in some individuals. Other studies have hinted at exposure to loud noise on a consistent basis. One study has shown a relationship of acoustic neuromas to prior exposure to head and neck radiation, and a concomitant history of having had a parathyroid adenoma (tumor found in proximity to the thyroid gland controlling calcium metabolism). There are even controversies on hand­held cell phones. It remains to be seen whether or not the radiofrequency radiation has anything to do with acoustic neuroma formation. To date, no environmental factor (such as cell phones and diet) has been scientifically proven to cause these tumors. ANA does recommend that frequent cell phone users use a hands­free device to enable separation of the device from the head. Please refer to cell phone statement on our website