What Is a Brain Tumor?

A brain tumor is an abnormal growth of cells in the brain or the membranes surrounding the brain (a tumor known as a meningioma). The tumor increases pressure inside the skull and so exerts pressure on the entire brain: this phenomenon is responsible for many of the symptoms of brain tumors regardless of whether they are benign or malignant (cancerous).

Primary brain tumors originate in the brain but are much less common than secondary, or metastatic, tumors, which spread to the brain from cancers elsewhere in the body. Symptoms tend to appear gradually and vary according to the area of the brain affected. Primary malignant brain tumors are rare, accounting for less than 2 percent of all cancers.

What Causes Brain Tumors?

  • The cause of primary brain tumors is unknown.
  • Metastatic tumors may spread from cancers of the lungs, liver, intestines, breast, skin, or other parts of the body.

Symptoms of Brain Tumors

  • Frequent headaches that are more painful when lying down
  • Vomiting, with or without nausea
  • Blurred or double vision
  • Seizures
  • Impaired thinking, mental confusion, or even coma
  • Other symptoms depend on the location of the tumor within the brain and may include weakness or unsteadiness, paralysis on one side of the body, dizziness, speech difficulty, memory loss, loss of the sense of smell or hearing, or personality change

Brain Tumor Prevention

  • Get regular checkups to detect cancers elsewhere in the body before they have a chance to spread.

Brain Tumor Diagnosis

  • A thorough patient history, physical examination and neurological examination are performed. A neuro exam is a series of tests used to evaluate nervous system function and measure physical and mental alertness.
  • CT (computed tomography) scans or an MRI (magnetic resonance imaging) may be necessary to locate the tumor.
  • PET scan (positron emission tomography) provides an image of brain activity by determining the rate at which the tumor absorbs glucose (a sugar).
  • A spinal tap or lumbar puncture (the use of a needle to remove and analyze a sample from the cerebrospinal fluid surrounding the spinal cord) is often performed. (However, spinal taps should not be performed if other diagnostic imaging techniques reveal evidence of a large mass that is exerting pressure on the brain. Under such circumstances a spinal tap is dangerous.)
  • A biopsy of the tumor will most likely be necessary to confirm the diagnosis.
  • Electroencephalography may be used to measure and assess electrical activity in the brain.
  • Cerebral arteriography may be used in preparation for surgery to outline the arteries supplying blood to the tumor.

How a Brain Tumor Is Treated

  • Tumors near the surface of the brain may be surgically removed. In many cases, however, it is only possible to remove a portion of a tumor, since taking it all out would cause unacceptable amounts of brain damage. Still, removing even part of it may afford a period of improvement by relieving pressure within the cranium.
  • Tumors deep within the brain may be treated with microsurgery, laser surgery, or radiation therapy.
  • For malignant primary tumors, surgery may be followed with radiation or chemotherapy. Surgery may also be preceded by radiation.
  • Your doctor may prescribe corticosteroids to reduce swelling of brain tissue, anticonvulsant drugs to control seizures, and pain relievers.

When to Call a Doctor

  • Call a doctor if you ever have a seizure.
  • Consult your doctor if you experience a severe, persistent headache, especially one that is worse in the mornings or when lying down.
  • Call a doctor if you experience double vision or if you notice weakness, numbness, or loss of sensation in the limbs.


Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference

Simeon Margolis, M.D., Ph.D., Medical Editor

Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 13 Oct 2011

Last Modified: 24 Oct 2014