Brain & Nervous System Health Center

An adult brain tumor is a disease in which abnormal cells form in the tissues of the brain.

There are many types of brain and spinal cordtumors. The tumors are formed by the abnormal growth of cells and may begin in different parts of the brain or spinal cord. Together, the brain and spinal cord make up the central nervous system (CNS).

The tumors may be benign (not cancer) or malignant (cancer). Benign brain tumors grow and press on nearby areas of the brain. They rarely spread into other tissues and may recur (come back). Malignant brain tumors are likely to grow quickly and spread into other brain tissue. When a tumor grows into or presses on an area of the brain, it may stop that part of the brain from working the way it should. Both benign and malignant brain tumors can cause symptoms and need treatment.

Brain tumors can occur in both adults and children. However, treatment for children may be different than treatment for adults. (See the PDQ summary on Childhood Brain and Spinal Cord Tumors Treatment Overview for more information on the treatment of children.)

For information about lymphoma that begins in the brain, see the PDQ summary on Primary CNS Lymphoma Treatment.

A brain tumor that starts in another part of the body and spreads to the brain is called a metastatic tumor.

Tumors that start in the brain are called primary brain tumors. Often, tumors found in the brain have started somewhere else in the body and spread to one or more parts of the brain. These are called metastatic brain tumors (or brain metastases). Metastatic brain tumors are more common than primary brain tumors.

The types of cancer that commonly spread to the brain are melanoma and cancer of the breast, colon, lung, and unknown primary site. The types of cancer that commonly spread to the spinal cord are lymphoma and cancer of the lung, breast, and prostate. About half of metastatic brain and spinal cord tumors are caused by lung cancer. Leukemia, lymphoma, breast cancer, and gastrointestinal cancer may spread to the leptomeninges (the two innermost membranes covering the brain and spinal cord).

See the following PDQ summaries for more information on cancers that commonly spread to the brain and spinal cord:

• Adult Hodgkin Lymphoma Treatment
• Adult Non-Hodgkin Lymphoma Treatment
• Breast Cancer Treatment
• Carcinoma of Unknown Primary Treatment
• Colon Cancer Treatment
• Melanoma Treatment
• Non-Small Cell Lung Cancer Treatment
• Small Cell Lung Cancer Treatment

The brain controls many important body functions.

The brain has three major parts:

• The cerebrum is the largest part of the brain. It is at the top of the head. The cerebrum controls thinking, learning, problem solving, emotions, speech, reading, writing, and voluntary movement.
• The cerebellum is in the lower back of the brain (near the middle of the back of the head). It controls movement, balance, and posture.
• The brain stem connects the brain to the spinal cord. It is in the lowest part of the brain (just above the back of the neck). The brain stem controls breathing, heart rate, and the nerves and muscles used in seeing, hearing, walking, talking, and eating.