Acoustic neuromas (also called vestibular schwannomas) are non-cancerous tumors that develop on the vestibular nerve connecting the brain and inner ear. This nerve is responsible for balance and hearing. Acoustic neuromas are rare and may grow slowly or not at all. The neuroma is the result of an abnormal growth of the Schwann cells that help insulate and support nerve fibers.
In rare instances, patients may also experience numbness in or around the affected ear, headaches, dizziness, or facial numbness. Facial paralysis is not usually caused by an acoustic neuroma. If facial weakness or paralysis is seen associated with a tumor that looks like an acoustic neuroma, then it is likely a facial nerve tumor (schwannoma).
An MRI is the most effective way to diagnose an acoustic neuroma. Hearing tests as well as equilibrium and balance tests may be useful in differentiating the nerve of origin in an acoustic neuroma.
If the neuroma is small and not causing serious symptoms, the doctor may choose to monitor the tumor every six to 12 months instead of pursuing immediate treatment. For some larger tumors, the doctor may recommend stereotactic radiosurgery. The goal of this procedure is to preserve hearing and nerve function. The procedure involves directing a precision beam of radiation directly at the tumor. The procedure is non-invasive and painless, with full results presenting in the months following the procedure. There is also less risk of damage to healthy tissues and structures than with traditional surgery.
Very large neuromas may require surgical removal. The surgery is performed under general anesthesia and involves removing the neuroma through a small opening in the skull or through the inner ear.
In some instances, it may not be possible to remove the tumor entirely due to its proximity to nerves and other brain structures. Short and long-term outcomes following surgery vary depending on the tumor size and position, as well as the overall health of the patient.
Since neuromas are not cancerous, they do not spread to other parts of the body; however, they can continue to grow and press on other important brain structures. Patients who undergo surgery for acoustic neuromas are normally instructed to have follow-up MRIs at one, two, five, and 10 years post-surgery in order to ensure that there is no regrowth of the tumor.