Merck Manual

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Quick Facts

Overview of Brain Tumors


The Manual's Editorial Staff

Last full review/revision Apr 2019| Content last modified Apr 2019
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What is a brain tumor?

A brain tumor is a growth in your brain that may or may not be cancer. Brain tumors may start in your brain or may have spread to your brain (metastasized) from another part of your body.

  • Brain tumors can cause serious problems even if they aren’t cancer, because your skull is hard and there's no space for the tumor to grow

  • As a brain tumor grows, it pushes on your brain and raises the pressure inside your skull, which can affect your entire brain and be quickly fatal

  • Brain tumors cause different symptoms depending on where they are in your brain

  • Common symptoms include headaches, personality changes, loss of balance, trouble concentrating, seizures, and clumsiness

  • In older people, brain tumor symptoms may be mistaken for dementia

  • Treatments may include surgery, radiation therapy, or chemotherapy

What are the symptoms of brain tumors?

Brain tumor symptoms may start suddenly or develop slowly over time. Symptoms include:

  • Headaches, especially if they happen more often or get worse when you lie down

  • Problems with mental function and mood, such as becoming withdrawn, moody, drowsy, or confused, or acting in ways that are a change from your usual personality

  • Feeling sick to your stomach and throwing up

  • Blurred vision

  • Dizziness, loss of balance, and clumsiness

  • Seizures

  • Being sleepy and confused

Depending on which area of the brain the tumor is in, it may affect:

  • Movement of an arm, a leg, or one side of your body

  • Speaking or understanding language

  • Your sense of hearing, smell, or sight

How can doctors tell if I have a brain tumor?

Doctors do tests such as:

  • MRI of the head

  • CT scan of the head

  • Spinal tap (doctors take out a small amount of fluid around the brain and spinal cord, using a needle placed in your lower back, to run tests on and look at under a microscope)

Sometimes doctors can tell what kind of tumor it is from the MRI or CT scan. Sometimes doctors do a biopsy of the tumor (take out part of the tissue to look at under a microscope).

How do doctors treat a brain tumor?

Doctors treat a brain tumor based on where it is and the symptoms you're having. Unlike tumors in other parts of your body, whether a brain tumor is a cancer or not isn't as important. Noncancerous tumors can cause severe brain problems too. Treatments include:

  • Surgery to remove the tumor

  • Treatments to lower the pressure in your skull—these include medicines, breathing devices, and tubes to drain extra fluid away from your brain

If you have a very small, noncancerous tumor that isn't causing many symptoms, doctors may leave it alone.

End-of-life issues

People with cancerous brain tumors may quickly become unable to make decisions about their medical care and end-of-life needs. If you have a cancerous brain tumor, speak to a counselor or social worker to help you create an advance directive. An advance directive is a plan to let your loved ones and doctors know what kinds of medical care you want toward the end of your life.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version

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