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Cancer InDepth: Brain Tumors

A brain tumor occurs when cells grow uncontrollably in the brain. Cancer occurs when cells in the body divide without control or order. If cells divide uncontrollably, they form a mass of tissue. The mass is called a growth or tumor. The term cancer usually refers to malignant tumors. These can invade nearby tissue and spread to other parts of the body. A benign tumor does not spread. But, it can continue to grow and press structures near it, causing symptoms.

Brain Tumor
Brain Tumor

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Types of Brain Tumors

There are two main types of brain tumors:

  • Primary
  • Secondary

Primary Brain Tumors

There are two types of primary brain tumors:

Benign tumors – these begin in brain cells and do not spread to other organs or normal tissue.

Malignant tumors – these begin in brain cells and then travel to other parts of the body. They are cancerous.

Secondary Brain Tumors

A secondary tumor is a tumor that has spread to the brain from another site in the body. It is also called a metastatic tumor. All metastatic tumors are malignant.

Other Brain Tumors

Rare types of brain tumors, such as pituitary adenomas, neuromas, spinal cord tumors, and hydatid cysts, are not covered in this report.

Anatomy, Physiology, and Pathophysiology

The brain is in the skull. Abnormal growth of any kind takes up space and compresses normal structures. If the compression is localized, that part of the brain begins to malfunction. The location of the abnormality may be determined by the brain function that is no longer working properly. If the compression involves the entire brain, its blood supply is reduced and different symptoms appear.

Who Is Affected

Primary brain tumors are the second most common cancer in children and young adults. They are the third most common cancer in people between the ages of 15 and 34 and fourth at ages 35 to 54. They are less common in older adults, where metastatic tumors are more likely to occur.

Causes and Complications

Ionizing radiation and several hereditary diseases are the only known causes of brain tumors. The cause of the majority of primary brain cancers is unknown. Viruses and environmental factors may play a role. The causes of secondary brain cancers are the factors that caused the cancer at the site of origin.

Brain tumors disrupt brain activity, causing a deterioration in activity and function. Tumors may affect anything the brain does, from memory to movement. They may even irritate the brain enough to cause a seizure. Other complications include headaches or personality changes.

This Report Covers the Following:

Risk factors – factors that increase your chances of developing a brain tumor.
Reducing your risk – steps you can take that may help decrease your risk of developing a brain tumor.
Screening – when you don't have symptoms of cancer, screening tests offer a way to determine if you are at risk for or if you have a brain tumor.
Symptoms – changes in your health that should prompt you to see your doctor for further evaluation.
Diagnosis and prognosis – the steps your doctor will take to find out if you have a brain tumor. If you do have a tumor, the testing that will determine how far it has progressed.
Treatment – the goals and options for treatment of brain tumors.
Living with a brain tumor – one man shares his experiences with a brain tumor.
Talking with your doctor – questions to ask your doctor.
Resources – places to go for further information on brain tumors.

Brain tumor. EBSCO DynaMed website. Available at: Updated May 28, 2013. Accessed June 4, 2013.

Brain tumor. National Cancer Institute website. Available at: Accessed June 4, 2013.

Last reviewed June 2013 by Mohei Abouzied, MD; Michael Woods, MD  Last Updated: 6/5/2013