Schwannoma is mostly a noncancerous (benign) tumor of the Schwann cells. In rare cases, it may turn into a malignant schwannoma, which is a cancerous growth. A vestibular schwannoma (also known as acoustic neuroma, acoustic neurinoma, or acoustic neurilemoma) is a benign, usually slow-growing tumor that develops from the nerve that supplies the inner ear that controls balance and hearing.
- As the tumor grows, it can interfere with the trigeminal nerve (the nerve that controls facial sensation), causing facial numbness.
- Vestibular schwannomas can also press on the facial nerve (for the muscles of the face) causing facial weakness or paralysis on the side of the tumor.
- If the tumor becomes large, it will eventually press against nearby brain structures (such as the brainstem and cerebellum), becoming life-threatening.
What are the symptoms of schwannoma?
A vestibular schwannoma comes from overproduction of the Schwann cells, which are the cells that normally grow around the nerve fibers and help support and insulate the nerves. As the vestibular schwannoma grows, it presses against the hearing and balance nerves and usually causes:
- Unilateral (one-sided) or asymmetric hearing loss.
- Tinnitus (ringing in the ear).
- Dizziness/loss of balance.
An acoustic neuroma can cause an array of chronic and serious symptoms that can result in disability. Physical and cognitive symptoms of an acoustic neuroma can be extremely limiting and distressing, which may lead to secondary emotional issues such as depression and anxiety. All these physical, cognitive, and secondary emotional issues can be disabling if they are present with enough severity and frequency.
What are the possible causes of a vestibular schwannoma?
The cause of an acoustic vestibular schwannoma is unknown and still being researched. However, the risk factors may include:
- It is most common in people aged between 40 and 60 years old, but it can affect people of any age.
- In a small population, vestibular schwannomas are linked to an inherited (genetic) condition called neurofibromatosis type 2 (NF2). In this situation, tumors usually develop on the hearing and balance nerves on both sides of the head.
- People who underwent radiation therapy for head and neck conditions during their childhood may have an increased risk of a vestibular schwannoma.
- Vestibular schwannoma is a rare brain tumor and is more common in women than in men.
Unilateral vestibular schwannomas
- They affect only one ear.
- They account for approximately eight percent of all tumors inside the skull, with 1 out of every 100,000 individuals per year developing a vestibular schwannoma.
- Symptoms may develop at any age but usually occur between 30 and 60 years of age.
- Unilateral vestibular schwannomas are not hereditary.
Bilateral vestibular schwannomas
- They affect both hearing nerves and are usually associated with a genetic disorder called NF2.
- Half of the affected individuals have inherited the disorder from an affected parent and half seem to have a mutation for the first time in their family. Each child of an affected parent has a 50 percent chance of inheriting the disorder.
- Individuals with NF2 usually develop symptoms in their teens or early adulthood. In addition, people with NF2 usually develop multiple brain and spinal cord–related tumors. They also can develop tumors of the nerves important for swallowing, speech, eye and facial movement and facial sensation.
Scientists believe that both unilateral and bilateral vestibular schwannomas form following the loss of function of a gene on chromosome 22, which produces a protein that controls the growth of the Schwann cells.
What are treatment options for a vestibular schwannoma?
There are several treatment options for an acoustic neuroma, depending on the size and position of your tumor.
Monitoring the tumor
- Small tumors often just need to be monitored with regular magnetic resonance imaging (MRI) scans, and doctors generally recommend the below treatments only if scans show the tumor getting bigger.
- Brain surgery: Doctors may perform surgery to remove the tumor through a cut in the skull under general anesthesia if it's large or getting bigger.
- Stereotactic radiosurgery: Doctors may treat small tumors or any pieces of a larger tumor that remain after the surgery with a precise beam of radiation to stop it from getting any bigger.
All these options carry some risks. Surgery and radiosurgery can sometimes cause facial numbness or an inability to move part of your face (paralysis). If the tumor is very small, the hearing function may be preserved, and accompanying symptoms may improve.
As the tumor grows larger, surgical removal becomes more complicated because the tumor may damage the nerves that control facial movement, hearing and balance and may also affect brain structures. When the tumor has affected these nerves, its surgical removal can worsen the person’s symptoms because sections of the nerves themselves may also need to be removed. In this case, vestibular rehabilitation may help promote central nervous system compensation for the inner-ear deficit.
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Schwannoma (Trigeminal & Acoustic): https://www.pacificneuroscienceinstitute.org/brain-tumor/conditions/schwannoma-trigeminal-acoustic/