Primary brain tumors arise from the brain, spinal cord, and associated tissues—collectively known as the central nervous system—rather than originating from cancerous cells that travel from elsewhere in the body. Primary brain tumors are categorized as either benign (noncancerous) or malignant (cancerous).
Despite their often slow growth, noncancerous primary brain tumors can still have devastating physical and emotional effects. Meningiomas, for example, can grow anywhere on the meninges (protective layers that cover the brain and spinal chord) and as a result can gravely affect areas of the brain needed for such functions as sight, hearing, touch, balance, memory, and judgment.
Research into the causes of brain tumors currently includes investigating environmental factors, exposure to certain viruses, and the role of genes. For most patients, there is generally no obvious exposure or risk factor that can be linked to these tumors.