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 cord tumors. 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 keep that part of the brain from working the way it should. Both benign and malignant brain tumors can cause symptoms and, sometimes, death.
Brain tumors can occur in both adults and children. However, treatment for children may be different than treatment for adults.
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).
The brain controls many important body functions.
The brain has three major parts:
The spinal cord connects the brain to nerves in most parts of the body.
The spinal cord is a column of nerve tissue that runs from the brain stem down the center of the back. It is covered by three thin layers of tissue called membranes. These membranes are surrounded by the vertebrae (back bones). Spinal cord nerves carry messages between the brain and the rest of the body, such as a signal from the brain to cause muscles to move or from the skin to the brain about the sense of touch.
There are different types of brain and spinal cord tumors.
Brain and spinal cord tumors are named based on the type of cell they formed in and where the tumor first formed in the CNS. The grade of a tumor may be used to tell the difference between slow- and fast-growing types of the tumor. The grade of a tumor is based on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread.
Tumor Grading System