Acoustic neuroma: A slow-growing tumor that requires specialized care

An acoustic neuroma, also known as a vestibular schwannoma, is a tumor of the hearing and balance nerve complex in the brain. They are rare, and account for less than 10% of all brain tumors. The tumor involves an area of the brain and ear called the lateral skull base; an acoustic neuroma can range in size, and it can cause a variety of troublesome symptoms related to hearing and balance.

It is important to note that although the diagnosis of a brain tumor can cause significant anxiety, acoustic neuromas are noncancerous and grow very slowly. This means that immediate treatment is rarely necessary.

What are the most common symptoms?

Acoustic neuromas can cause you to experience a variety of symptoms. In general, the first thing you may notice is hearing loss in one ear greater than the other, ringing in the ears (tinnitus), and/or dizziness or imbalance (acute or chronic). These symptoms can range from mild to very distressing and bothersome. It is important to note that these symptoms are not related to the size of the tumor. Some people can have a very small tumor with significant hearing loss and imbalance, while other people can have very large tumors with few symptoms. If you are experiencing any or all of these symptoms, you should seek the attention of your physician.

How are acoustic neuromas diagnosed?

If symptoms of hearing loss, tinnitus, or imbalance are present, you will likely be referred to an ear, nose, and throat specialist (ENT) for evaluation. Commonly, with these symptoms you will be asked to undergo a hearing test. If you are dizzy, additional balance testing may be performed. If there are any abnormalities on either of these tests that demonstrate unequal function (asymmetrical hearing loss), you may undergo imaging of the inner ears and head with an MRI to check for an acoustic neuroma. An MRI can help accurately diagnose an acoustic neuroma because the characteristics of these tumors look particularly unique compared to other brain tumors.

What if the MRI doesn’t show an acoustic neuroma?

Because acoustic neuromas are rare, MRI scans are often normal in patients with symptoms of hearing loss, tinnitus, and dizziness, and it is very unlikely that you have an acoustic neuroma with a normal MRI. However, this does not mean that you do not have the symptoms, and additional testing of these symptoms may be necessary. Talking to your doctor about symptom management is important, no matter what the MRI scan reveals.

What is the next step if I am diagnosed with an acoustic neuroma?

If you are diagnosed with an acoustic neuroma, the amount of information you receive can seem overwhelming. It is important to know that decisions for treatment rarely need to be made immediately. After diagnosis, your next step may involve referral to a specialist.

You should expect a team of specialist doctors to be involved in your care, including ENTs with specialty training (neuro-otologists), neurosurgeons, and/or a radiation oncologist and a physical therapist.

The team of physicians and clinicians involved in the care of acoustic neuromas will often work together to coordinate a plan that optimizes your needs.

Treatment options

Before your visit with the specialist, you should take time to prepare and ask about the various treatment options. The treatment approach will be individualized based on your specific tumor and your personal health situation; however, there are three main options for treatment:

• Observation of these tumors without intervention is possible because of their slow-growing, benign nature. If you decide to observe your acoustic neuroma, repeat MRIs will be necessary to monitor for tumor growth.
• Surgery or microsurgery has various indications, and there are a variety of surgical approaches. The goal with surgery is to remove the tumor and preserve important structures near it. If you elect to have surgery for your acoustic neuroma, the approach should be a joint decision between you and your surgeon.
• Radiation therapy is also an option for acoustic neuromas. With this treatment approach, your tumor will not be removed; rather, the goal is to stop the growth of the tumor. Treatment courses are variable and may include a single treatment or multiple treatments over the course of weeks.

There are a few factors that physicians use when deciding on your treatment approach: your age, the size of your tumor, and your hearing status. While each of these factors will be considered for your specific tumor, there are no specific treatment guidelines, and there is no right answer or single treatment approach that is best. In general, in younger patients and larger tumors surgery may be favored, while in older patients or patients in poor health, nonsurgical options may be offered.

Regardless of the treatment option you elect to pursue, hearing rarely improves, although preservation of existing hearing is possible in some cases. If you choose to observe your tumor, changes in your hearing may still occur, as it is difficult to predict what factors lead to hearing changes in this setting. Similarly, it is important to know that after treatment your balance will temporarily be worse, and physical therapy may be necessary to regain balance.

Take-home message

Acoustic neuromas are rare brain tumors that often have a range of symptoms from mild to bothersome. The treatment options are very complex and require specialized care. If you are diagnosed with an acoustic neuroma, the most important thing to know is that there is often time to make an informed decision, and your treatment team can help you manage your symptoms and personalize your care.

Additional resources can be found at the Acoustic Neuroma Association.