There are many types of brain and spinal cord tumors. Together, the brain and spinal cord make up the central nervous system (CNS).
The tumors may be either benign (not cancer) or malignant (cancer). Tumors that start in the brain are called primary brain tumors.
Primary brain tumors may spread to other parts of the brain or to the spine, but they rarely spread to other parts of the body. 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.
SEER Cancer Stat Facts: Brain and Other Nervous System Cancer. National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/statfacts/html/brain.html