by Polsdorfer R

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. A brain tumor starts in a type of brain cell.

Brain Tumor
Brain Tumor
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Types of Brain Tumors

There are 2 main types of brain tumors:

  • Primary
  • Secondary
Primary Brain Tumors

There are 2 types of primary brain tumors:

Benign tumors–these tumors are not cancer. They do not spread to other organs or normal tissue.

Malignant tumors–these tumors are cancer. They spread to nearby tissue and can spread to other parts of the body.

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 cancer.

Other Brain Tumors

These pages will focus on more common types of tumors. Rare types such as pituitary adenomas, neuromas, and spinal cord tumors will not be covered.

How Cancer can Affect the Brain

The brain has limited space in the skull. The growth of a tumor will start to decrease free space in the skull. The tumor itself can put pressure on nearby tissue. This tissue may also cause pressure against the skull or make it hard for fluids to move freely inside the skull. The increased pressure can make it hard for the brain to work as it should. Pressure in one area can cause specific problems such as loss of sight or speech. Some growths can lead to swelling in the entire brain. This can lead to very severe symptoms.

Brain tumors disrupt brain activity. It leads to problems in movement, body functions, and thought process or behaviors. They may even irritate the brain enough to cause a seizure.

Who Is Affected

Primary brain tumors are a common cause of cancer in children and young adults. They are also a common type of cancer in people between the ages of 15 to 54.

Metastatic tumors are more common in older adults.


Ionizing radiation and hereditary diseases are the only known causes of brain tumors. The cause of the majority of primary brain cancers is unknown. Viruses and things in the environment may play a role.


Astrocytoma and Oligodendroglioma in Adults. EBSCO DynaMed website. Available at: . Updated September 20, 2019. Accessed January 9, 2020.

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

Revision Information

  • Reviewer: EBSCO Medical Review Board Mohei Abouzied, MD, FACP
  • Review Date: 09/2020
  • Update Date: 12/15/2020