What is a Vestibular Schwannoma?

A vestibular schwannoma is a noncancerous tumor that develops along the vestibular or cochlear nerve in the head. The nerves involved contribute to balance and hearing, and a large tumor can seriously damage both senses. A person may develop a ringing sensation in one ear, frequent headaches, dizzy spells, and a gradual loss of hearing. Schwannomas usually grow very slowly, and they may not cause symptoms for many years or decades after they begin to form. Surgery is the preferred treatment for a vestibular schwannoma.

Medical researchers are not certain why most vestibular schwannomas develop, though tumors are thought to arise because of non-inherited genetic mutations. Genes that contribute to the production of Schwann cells may be damaged, missing, or malformed in people who have vestibular schwannoma complications. Schwann cells normally form part of the protective lining of neurons. Schwannomas develop when cells around the vestibular or cochlear nerves grow in unusual patterns.

In the early stages of tumor growth, a person may not have any symptoms at all. Problems first tend to appear between the ages of 30 and 60 as tumors grow large enough to put pressure on the underlying nerves. Tinnitus, or ringing in the ear, is the most prominent symptom for many patients. Hearing loss on one side of the head is typically a slowly worsening, permanent complication. A person may also develop vertigo and have trouble keeping his or her balance when walking or standing. If a tumor goes untreated, it can become large enough to compress the nearby trigeminal nerve and lead to muscle weakness or partial paralysis in the face.

The symptoms of a vestibular schwannoma can be very similar to other types of ear disorders. Doctors usually perform a series of diagnostic tests to determine the true causes of patients' hearing and balance problems. Magnetic resonance imaging and computerized tomography scans are useful in looking for such physical problems as schwannomas. Patients also participate in various hearing and equilibrium tests to determine how severe their symptoms have become.

In most cases, a vestibular schwannoma can be removed surgically. A trained surgeon can excise the tumor through a small incision made underneath the ear, taking extreme precaution not to accidentally damage underlying nerves and muscle tissue. If surgery is not possible because of the patient's age or health, radiation treatments may be performed in an attempt to shrink the tumor. Surgery or radiation usually cannot restore a patient's original hearing, but early treatment can put an end to many uncomfortable symptoms and prevent further hearing loss.