Vestibular Schwannoma

What is a Vestibular Schwannoma?

A vestibular schwannoma, sometimes referred to as acoustic neuroma, is a benign tumor found on the vestibularcochlear nerve, the nerve that connects the ear to the brain. This nerve is behind the ear, right under the brain. This type of tumor is typically very slow- growing, and it may press against the nerves controlling hearing and balance as it grows. An acoustic neuroma is an uncommon cause of hearing loss. If the tumor remains small, many patients will remain asymptomatic. However, if it enlarges enough to exert serious pressure on the brain, it may become life-threatening.

Causes of a Vestibular Schwannoma

Most of the time, the cause of a vestibular schwannoma is unknown. If vestibular schwannomas develop in both auditory nerves, the underlying cause may be a heredity disorder known as neurofibromatosis type 2, but this genetic defect accounts for only a very small percentage of cases. The vast majority of vestibular schwannomas are sporadic (non-inherited).

Symptoms of Vestibular Schwannoma

Many patients with small vestibular schwannomas will not be symptomatic. As it grows, it presses against the hearing and balance nerves, and large tumors may press against the brain and brainstem. Pressures on these structures generates symptoms. These symptoms may include:

Loss of hearing in one ear
Balance problems
Ringing in the ears, also known as tinnitus
Difficulty swallowing and hoarseness
Headaches
Clumsiness or unsteadiness
Confusion
Numbness
Facial paralysis

Diagnosis of a Vestibular Schwannoma

There are several ways a physician may diagnose a vestibular schwannoma. The physician may evaluate the ears, balance system, and mobility of the face. It is possible, however, that there will be no physical evidence of the tumor. The following diagnostic tests may be administered to detect the presence of a vestibular schwannoma.

Hearing test (audiogram)
Auditory brain stem response, or ABR
Electronystagmography (ENG) or videonystagmography (VNG)
MRI scan of the brain

Treatment of a Vestibular Schwannoma

When a vestibular schwannoma remains small, the patient may only need regular checkups and surveillance for growth. Tumors that demonstrate active growth may require treatment with radiation or surgical removal. Radiation is designed to halt tumor growth while surgery facilitates tumor removal. The decision of which treatment to pursue is dependent on many factors, which will be discussed in depth between the patient and the physician.

Risks of Treatment for Vestibular Schwannoma

There are risks associated with both radiation and surgery for treatment of a vestibular schwannoma. With radiosurgery, risks may include partial or total hearing loss in the affected ear, dizziness, facial weakness, or brain swelling.

If typical surgery is required for the treatment of a vestibular schwannoma, risks may include: