What is an acoustic neuroma? (vestibular schwannoma)

An acoustic neuroma is a benign growth which arises from the hearing and balance nerve that originates from the lower portion of the brain stem. These tumors represent approximately six percent (6%) of all brain tumors.

Is the tumor benign?

Yes. Acoustic neuromas are benign fibrous growths that are non-malignant, meaning that they do not spread or metastasize to other parts of the body. These tumors are, by nature, very slow growing in general. They affect adjacent nervous structures by creating pressure on these structures.

If I have an Acoustic Neuroma, are my children at risk for developing it, too?

The majority of acoustic neuromas are unilateral and are not hereditary. Ninety-five percent (95%) of cases are sporadic and only involve one side. This is in contrast to those tumors which are associated with a hereditary disease called Neurofibromatosis Type II (NF II). In these patients, the acoustic neuromas are bilateral. This condition is hereditary. NF II is a rare disease and it is found in approximately one person per one hundred thousand population in the United States. If someone is diagnosed with NF II, they should undergo genetic counseling.

Why me? What causes these tumors to develop?

The exact cause of acoustic neuromas is not currently known. There is ongoing research at the House Ear Institute and other centers to try and determine the genetic defects that occur in the tumor cells. However, no specific environmental agents have been identified which causes the development of an acoustic neuroma.

Does my acoustic neuroma have to be treated?

The majority of patients who present with an acoustic neuroma do have treatment of the tumor. However, these are benign, very slow growing tumors in the vast majority of cases. Therefore, it should be understood that it is rarely an emergent situation to undergo treatment once this tumor is diagnosed. Patients have time to research their options for treatment and find an experienced team to manage their care. Those who do elect to be observed and not undergo surgery for the tumor, in general, do not exhibit significant changes in the tumor over time as documented by frequent MRI scans. In a recently reviewed series of one hundred and nineteen (119) mostly elderly patients followed conservatively at the House Ear Clinic over a two and a half (2 1/2) year average follow-up time, seventy percent (70%) of the patients did not exhibit any growth of their tumor. Those that did exhibit growth or developed new symptoms went on to have surgical removal of the tumor.

Are there support organizations I can contact for information?

Yes. The "Acoustic Neuroma Association" is an excellent source of information. The organization provides educational material regarding acoustic neuromas and the various forms of treatment and can put you into contact with its local support group organizations.

What are the chances I will lose my hearing?

The chances of losing hearing prior to treatment depend upon many factors. Patients lose hearing due to these tumors from pressure effects of the tumor on the auditory nerve, as well as, invasion of the auditory nerve by the tumor. Similarly, the tumor can cause an obstruction of blood flow to the auditory nerve and the cochlea which results in hearing loss. Most patients present with hearing loss as the first symptom of their acoustic neuroma.

The chances of losing hearing completely after surgery are dependent upon the size of the tumor and the level of hearing before treatment. Patients with poor hearing before treatment have a very low chance, with any therapy, of having their hearing preserved. Patients with better hearing have a much better chance of having their hearing preserved. As noted above, in a recent series of over three hundred and eighty (380) patients with small tumors treated by the middle fossa approach here at the House Ear Clinic, roughly two thirds (2/3) of patients had their hearing preserved at a functional level. Eighty percent (80%) of patients maintained at least some measurable hearing which, in many cases, was good enough for them to use the telephone with that ear.

What is the chance of losing facial nerve function?

An occasional patient presents with facial nerve weakness as the first symptom of their acoustic neuroma. These patients tend to be those with larger tumors. The risk of losing facial nerve function as a consequence of surgical treatment is dependent upon the size of the tumor. Patients with small tumors have an excellent chance of having excellent facial nerve function after surgery. Patients with small tumors can expect a ninety-five (95%) chance of excellent nerve function, as judged by our recent review of patients with small tumors treated at the House Ear Clinic with a middle fossa approach. Only five percent (5%) had what is considered good facial nerve function, which translates to a grade 3 on the House/ Brackmann scale.

What is the chance the tumor will come back after treatment?

The chance of recurrence after surgical complete resection is extremely low. A study of over three thousand patients with acoustic neuromas who had their surgery at the House Ear Clinic demonstrated that the recurrence rate after total resection was 0.2% in these patients. Recurrence rates in other surgical series have, in general, been in the zero to two percent (0-2%) range after total resection.

What type of doctor should I be consulting about my acoustic neuroma?

Ideally, a neurosurgeon or neuro-otologic surgeon who has experience with the treatment of acoustic neuromas should be consulted. Many specialized teams exist at several centers around the country who have the necessary experience and frequently treat patients with acoustic neuromas. These are difficult problems that are best handled by an experienced, multidisciplinary team in order to provide the best chance for a good outcome. It is important to find out the level of experience of the physician that is consulted. Patients should not be bashful in asking how many acoustic neuromas the doctor has treated within the past year, or in the past five to ten years, and what the results of that treatment were. Patients should expect to receive specific answers based on a review of the physician's own personal data. It is important to find out the physician's personal results with preservation of facial nerve function, hearing preservation, and the incidence of other major complications with either surgery or radiosurgery. Patients should probably be wary if a surgeon does not have easily produced statistical results (this usually means that he/she does not frequently treat these tumors). Likewise, patients should be wary of being treated by a physician who only occasionally treats this complicated problem.

Is this a tumor that any general neurosurgeon or otolaryngologist should be treating?

Again, the experience of the surgeon and sub-specialty training influences outcome to a tremendous degree. Patients should seek out an experienced team who frequently treats these tumors and can give sound advice based upon adequate experience.

House Ear Clinic CONSULTATIONS

If you, a family member, or someone you know has been diagnosed with an acoustic neuroma, you may consult with a doctor from the House Ear Clinic team. We will be happy to review the MRI scans and audiogram and speak with you by telephone (we must have a copy of the actual MRI film, reports are not sufficient by themselves).

Send the MRI scans by express delivery (be sure that you are able to track the package) to:

House Ear Clinic
Attn: Acoustic Neuroma Website Consultations
2100 W. Third Street, 1st Floor
Los Angeles, CA 90057

You can expect to hear from a House Ear Clinic physician within 24 hours of our receipt of your information. You may also call or fax a House Ear Clinic physician at:

Telephone: (213) 483-9930
FAX: (213) 484-5900

This mail/telephone consultation is free of charge. (This offer does not apply to office consultations.)

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