Mayo Clinic: I was diagnosed with an acoustic neuroma last
year. My doctor says I likely won’t need treatment. But I
know others who have had the same condition and had surgery to
remove the tumor. Why would I not need any treatment?
acoustic neuroma, more accurately called a vestibular
schwannoma, is a benign tumor that grows on the balance and
hearing nerves. These nerves twine together to form the
vestibulocochlear nerve, which runs from your inner ear to
your brain. Hearing loss due to an acoustic neuroma often
occurs predominantly on one side only. For many years, doctors
thought surgical removal was the best treatment. Then, in the
mid-1980s, stereotactic radiosurgery, such as Gamma knife
radiosurgery, was shown to be safe and effective.
Increasingly, doctors are concluding that, in some cases, no
treatment may be just as good as or better than active
intervention in the long run.
acoustic neuroma arises from the cells (Schwann cells) that
make up the insulation surrounding the vestibulocochlear
nerve. What causes these cells to overgrow and form a tumor
isn’t certain, but it may be related to sporadic genetic
defects. Acoustic neuromas are uncommon and usually are
diagnosed between ages 30 and 60. In rare cases, the
overgrowth may be caused by an inherited disorder, called
neurofibromatosis type 2.
acoustic neuromas grow very slowly, although the growth rate
is different for each person and may vary from year to year.
Some acoustic neuromas stop growing, and a few even
spontaneously get smaller. The tumor doesn’t invade the
brain but may push against it as it enlarges.
and symptoms typically include loss of hearing in one ear,
ringing in the ear (tinnitus) and unsteadiness while walking.
Occasionally, facial numbness or tingling may occur. Rarely,
large tumors may press on your brainstem, threatening vital
functions. A tumor can prevent the normal flow of fluid
between your brain and spinal cord so that fluid builds up in
your head — a condition caused hydrocephalus.
can be a challenge because early signs and symptoms may be
attributed to more familiar causes, such as aging or noise
exposure. If an acoustic neuroma is suspected, such as when a
hearing test reveals loss predominantly in one ear, the next
step is to undergo imaging — typically an MRI — to look
for evidence of a tumor on the vestibulocochlear nerve.
Increasingly, acoustic neuromas are being discovered as
incidental findings when people undergo an MRI scan for
unrelated reasons, such as chronic headache, multiple
sclerosis or even during surveillance imaging for another
varies depending on the size and growth of the acoustic
neuroma, symptoms, and your personal preferences. Options
Monitoring. If you have a small acoustic neuroma that isn’t
growing or is growing slowly and causes few or no signs or
symptoms, your doctor may decide to monitor it. It sounds like
this is what your doctor has recommended for your situation.
Recent studies indicate that more than half of small tumors
don’t grow after diagnosis, and a small percentage even
shrink. Monitoring involves regular imaging and hearing tests,
usually every six to 12 months. The main risk of monitoring is
tumor growth and progressive hearing loss.
Stereotactic radiosurgery. This approach may be used if the
acoustic neuroma is growing or causing signs and symptoms. In
this procedure, doctors deliver a highly precise, single dose
of radiation to the tumor. The procedure’s success rate at
stopping tumor growth is usually greater than 90 percent.
Although the risk is small, stereotactic radiosurgery can
damage nearby balance, hearing and facial nerves, worsening
symptoms or creating new ones.
surgery. Surgical removal typically is recommended when the
tumor is large or growing rapidly. This involves removing the
tumor through the inner ear or through a window in your skull.
If it can be removed without injuring the nerves, your hearing
may be preserved. Surgery risks include nerve damage and
worsening of symptoms. In general, the larger the tumor, the
greater the chances of your hearing, balance and facial nerves
being affected. Other complications may include a persistent
is ongoing to compare the three treatment strategies. But,
based on long-term data, there appears to be surprisingly
little difference in outcome no matter which treatment is
chosen for smaller tumors. Talk to your doctor to make sure
you are being monitored appropriately for your situation.