Tumor - acoustic
Key points
- An acoustic neuroma is a benign, noncancerous, often slow-growing tumor of the nerve that connects the ear to the brain (8th cranial or auditory) nerve.
- These tumors are thought to arise when there is a defect in a certain tumor suppressor gene, which normally prevents tumors from occurring.
- The symptoms vary with the size and location of the tumor.
- The health care provider may diagnose an acoustic neuroma based on the history, neurological examination or testing of the patient.
Alternative names
Vestibular schwannoma; Acoustic neuroma; Cerebellopontine angle tumor; Angle tumor
Definition
An acoustic neuroma is a benign, noncancerous, often slow-growing tumor of the nerve that connects the ear to the brain (8th cranial or auditory) nerve.
Causes, incidence, and risk factors
These tumors are thought to arise when there is a defect in a certain tumor suppressor gene, which normally prevents tumors from occurring. The cause of the genetic defect is not known. However, acoustic neuroma is often linked with the genetic disorder neurofibromatosis type 2 (NF2).
Acoustic neuromas are relatively uncommon, but they are one of the most common types of brain tumors. They affect approximately 1 out of 100,000 people per year.
The tumor is most commonly located at the base of the brain, where the auditory nerve leaves the skull cavity and enters the bony structure of the inner ear.
Symptoms
The symptoms vary with the size and location of the tumor. Because the tumors grow so slowly, symptoms usually arise after the age of 30.
Common symptoms include:
- tinnitus (ringing) in the affected ear
- hearing loss in the affected ear
- vertigo (an abnormal sensation of movement)
Less common symptoms include:
- headache
o upon awakening in the morning
o which awakens patient from sleep
o aggravated by lying down, reclining position
o aggravated by standing up
o aggravated by coughing, sneezing, straining, lifting (Valsalva maneuver)
o with nausea or vomiting - difficulty understanding speech (out of proportion to total hearing loss)
- dizziness
- loss of balance
- numbness in the face or one ear
- pain in the face or one ear
- transient vision abnormalities
Signs and tests
The health care provider may diagnose an acoustic neuroma based on the history, neurological examination or testing of the patient. The results of a physical examination are often unremarkable, except for the following signs:
Written and revised by
Andrey Nailor, M.D.
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