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Vestibular Schwannoma/Acoustic Neuroma

Vestibular schwannoma, also known as acoustic neuroma, is a benign (noncancerous) tumor that develops on the balance and hearing nerves leading from your inner ear to the brain. These nerves are twisted together and form the vestibulocochlear nerve, also known as the eighth cranial nerve. A vestibular schwannoma takes its name from this nerve and from the Schwann cells covering it, which are the cells where the tumor originates.


You might not immediately notice a vestibular schwannoma because they typically grow slowly. But as the tumor grows, it starts to press against the nerves, leading to several symptoms:

  1. Loss of hearing on one side, often the first sign.
  2. Ringing (tinnitus) in the affected ear.
  3. Dizziness or loss of balance.
  4. Feeling of fullness in the ear.
  5. Facial numbness or weakness.
  6. In rare cases, larger tumors may cause headaches or confusion.


In most cases, the cause of acoustic neuromas is unknown. However, a small number of cases are linked with a syndrome called neurofibromatosis type II (NF2). NF2 is a hereditary condition characterized by the growth of benign tumors on the balance nerves on both sides of the head (bilateral vestibular schwannomas).


Your doctor may use several tests to diagnose vestibular schwannoma:

  1. Hearing test (audiometry): In this test, you listen to sounds through headphones and indicate when you can hear them. This can detect hearing loss in one ear, a common sign of an acoustic neuroma.
  2. Magnetic Resonance Imaging (MRI): This is the most common test used to diagnose an acoustic neuroma. An MRI can visualize the tumor and may be used to monitor its growth over time.
  3. Balance test: This might be performed to assess whether the vestibular schwannoma is affecting your balance.


Treatment for a vestibular schwannoma depends on a number of factors, including the size of the tumor, your overall health, and your personal preferences. Options include:

  1. Observation: Small, slow-growing tumors that don’t cause symptoms may not need immediate treatment. Regular imaging tests will monitor its growth.
  2. Surgery: There are various surgical techniques, depending on the size and location of the tumor and its impact on hearing.
  3. Radiation therapy: This uses high-energy rays to destroy the tumor. It’s usually done in a single dose of radiation (stereotactic radiosurgery), but sometimes it’s given in smaller doses over several treatments.

Potential Side Effects of Treatment

All treatments carry the risk of side effects. For vestibular schwannoma, these might include:

  1. Hearing loss: This could be a result of the tumor itself or as a side effect of surgery or radiation therapy.
  2. Facial nerve damage: Since the facial nerve is located close to the vestibulocochlear nerve, it might be affected during treatment, leading to facial numbness or weakness.
  3. Balance problems: These might continue after treatment, especially if they were a symptom before treatment.

Risks Associated with Each Management Option

Please note that individual risks can vary depending on multiple factors including the size and location of the tumor, the patient’s overall health, age, and specific medical condition:

Observation: During observation, the tumor is monitored for growth with periodic MRI scans. According to studies, about 50-60% of acoustic neuromas do not grow during the first few years of observation. However, if the tumor does grow, it may lead to worsening symptoms over time.

Surgery: Risks associated with surgical removal of an acoustic neuroma can vary widely, but in general:

Hearing loss in the affected ear occurs in a significant number of cases. Studies show that it can range anywhere from 30% to over 90%, depending on the tumor size and surgical technique used.

Facial nerve weakness or paralysis can occur in about 15-50% of patients immediately after surgery, but this often improves over time. Permanent facial nerve damage occurs in approximately 3-7% of cases.

A small percentage of patients may develop other complications, such as balance problems, cerebrospinal fluid leaks, infections, or stroke.

Mortality rates from acoustic neuroma surgery are quite low, typically around 0.2-0.5%.

Radiosurgery: Radiosurgery involves the delivery of targeted radiation to the tumor. It carries a low risk of complications:

Hearing loss can occur after radiosurgery, but the risk is generally lower than with surgical removal. Studies suggest that about 30-70% of patients retain useful hearing in the treated ear after radiosurgery.

Facial nerve damage is rare after radiosurgery, with reported rates usually below 3%.

Other complications, such as balance problems or tinnitus, are infrequent and typically mild when they do occur.


The prognosis for someone with a vestibular schwannoma is generally very good. Because these tumors are benign, they don’t spread (metastasize).