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Many people chalk up hearing loss to getting older. And often, that’s correct. But when someone notices hearing loss in just one ear or starts experiencing subtle balance problems along with it, it may not be age-related at all. In some cases, these symptoms are caused by a vestibular schwannoma – a benign, slow-growing tumor.
It’s estimated that 1.2 out of 100,000 people in the U.S. each year will develop a vestibular schwannoma. Often, these noncancerous tumors don’t cause symptoms. They’re found by happenstance during an MRI for an unrelated concern, such as a head injury or chronic headaches. Today’s MRI technology is more sensitive and used more often, and we’re seeing more cases of vestibular schwannoma than we used to.
Most of these tumors do not require immediate treatment beyond monitoring. However, there are cases in which symptoms interfere with daily life, or the size or location of the tumor threatens long-term hearing or balance.
Understanding what a vestibular schwannoma diagnosis means for you – and what it doesn’t – can go a long way toward easing anxiety and helping you make informed decisions about your care.
What is a vestibular schwannoma?
Vestibular schwannomas arise from Schwann cells, which form the protective covering of nerves. These tumors typically develop on the vestibular nerve, which is responsible for balance. This nerve travels from the inner ear to the brain alongside the hearing nerve (vestibulocochlear, or acoustic, nerve) and facial nerve (cranial nerve VII).
Vestibular schwannomas are sometimes called acoustic neuromas. But this older term can be misleading; a neuroma is a painful growth, and “acoustic” refers to the hearing nerve. Vestibular schwannomas usually don’t cause pain and are not located on the acoustic nerve.
About 90% of vestibular schwannomas are sporadic, meaning that a single Schwann cell randomly developed a mutation and formed a tumor. About 90% are solitary, meaning the patient has just one tumor. In rare cases, multiple and disruptive vestibular schwannomas can be caused by a genetic disorder, such as NF2-related schwannomatosis (NF2-SWN), which causes recurrent, systemic tumors and significant hearing loss early in life.
Related: Read "What causes hearing loss and how to prevent it"
Symptoms of vestibular schwannoma
Vestibular schwannoma symptoms can vary widely. Some people have noticeable changes, while others have none for many years.
While a vestibular schwannoma develops on the nerve that affects balance, hearing loss tends to be the first sign of a problem. As the tumor grows, it begins to press on the acoustic nerve, which is right next door. Over time, the vestibular schwannoma can also crowd the facial nerve, which can cause weakness, loss of muscle movement, or decreased sensation in the face.
Common symptoms of vestibular schwannoma include:
- Hearing loss in one ear that occurs gradually over months or years
- Ringing in the affected ear, known as tinnitus
- Balance problems or dizziness
- Facial numbness or a tingling sensation in the face
Most vestibular schwannoma symptoms develop slowly. Many of the most common symptoms, particularly hearing loss, do not reliably improve with treatment. Larger tumors that are growing are likely to get bigger, but there is no perfect calculation to predict future growth. Ongoing monitoring is key to providing the appropriate treatment at the right time.
Treatment options for vestibular schwannomas
There are three main strategies for managing vestibular schwannomas: observation, radiosurgery, and surgery. The right choice depends on tumor size, growth rate, symptoms, hearing status, age, and the patient’s preference.
Vestibular schwannomas usually grow at a rate of about 1 millimeter a year, about the thickness of a credit card. However, some may grow faster and some slower. Sometimes they stay the same size for years and then suddenly start growing again. We consider a vestibular schwannoma less than 10 millimeters to be small, 10 to 20 millimeters to be medium, 20 to 30 millimeters large, and more than 30 millimeters extra large.
Observation (watchful waiting)
Observation, or watchful waiting, is very common, especially for small tumors and for patients with minimal symptoms. Periodic visits will involve MRI scans to track tumor growth and exams to monitor symptoms, such as hearing loss. Generally, we will do an MRI six months after the tumor is discovered. Then, depending on the initial tumor size and growth rate, we will recommend annual MRIs until something changes.
Stereotactic radiosurgery
Radiosurgery is a non-invasive procedure that uses narrow, highly focused beams of radiation to treat the tumor while limiting radiation exposure to the surrounding healthy tissue. We use Gamma Knife technology to deliver the radiation, and it usually only takes one treatment session.
Rather than removing the tumor, the goal of radiosurgery is to stop the tumor from growing. This is a good option for medium/large tumors or symptomatic vestibular schwannomas or for people who cannot safely have surgery to remove the tumor.
Surgery
You may need surgery to remove the vestibular schwannoma if it is large, if it continues to grow, or if your symptoms get worse. There are several techniques UT Southwestern surgeons can use to remove a vestibular schwannoma, including:
- Transpromontorial approach: Also known as invisible acoustic neuroma surgery, this procedure uses a small incision in the ear canal to remove a small amount of bone and extract the tumor. The approach leaves no visible scarring behind the ear or in the scalp. UTSW was one of first centers in the country to offer this innovative technique.
- Retrosigmoid approach: Also known as suboccipital craniotomy, this is the classic technique to remove vestibular schwannomas. The surgery requires a 2- to 3-inch incision behind the ear that extends into the upper neck.
- Middle fossa approach: A standard technique that requires a 2-inch incision in front of the ear that runs up to the scalp.
- Translabyrinthine approach: This common technique requires a 3-inch incision above and behind the ear.
In some cases, removing the tumor can damage the surrounding facial or auditory nerves. Your care team will help advise you on choosing the best approach for your condition. We will recommend the most appropriate treatment based on the tumor’s size and location as well as your hearing status.
While surgery and radiosurgery are highly effective treatment options for vestibular schwannomas, neither will restore your natural hearing. However, we can sometimes preserve remaining hearing in the affected ear if the tumor is small and in an ideal location.
Many patients choose to use hearing aids before or after treatment. Depending on your level of hearing loss, we also can discuss whether a cochlear implant might be right for you.
Choose an expert team for your care
Vestibular schwannomas affect structures that are critical to hearing, balance, facial sensation, and brain function. Patients get the best outcomes at centers that treat a large number of patients with the condition, with dedicated specialists who work as a team.
At high-volume centers such as UT Southwestern, vestibular schwannoma care often involves:
- Neurotologists (ear and skull base specialists)
- Neurosurgeons
- Radiation oncologists
- Audiologists and hearing specialists
- Vestibular and facial rehabilitation therapists
This collaborative approach allows each expert to focus on their area of strength, improving each patient’s outcomes. Our patients get access to the latest emerging therapies through clinical trials. For example, we are one of four locations in the U.S. participating in a clinical trial involving a new gene therapy to control tumor growth. This could become an exciting potential alternative to conventional radiosurgery or surgery.
Being told you have a tumor, even if it is benign, can be alarming. But it’s important to know that vestibular schwannomas are not cancerous. They usually grow slowly, and we almost always have time to make thoughtful, effective treatment decisions together.
To talk with an expert about vestibular schwannoma care, make an appointment by calling 214-645-8898 or request an appointment online.
