What is the difference between a primary brain tumor and a metastatic (secondary) brain tumor?
Primary brain tumors originate in the brain itself. Primary brain tumors do not spread from the brain to other parts of the body except in rare cases. Pathologists classify primary brain tumors into two groups: glial tumors (gliomas) and nonglial tumors. Gliomas are composed of glial cells, which include astrocytes, oligodendrocytes, ependymal cells, Schwann cells, microglia, and satellite cells. Nonglial tumors develop on or in structures within the brain, such as nerves, blood vessels, and glands. Metastatic or secondary brain tumors begin as cancer in another part of the body. Some of the cancer cells may be carried to the brain by the blood or may spread from adjacent tissue. The site where the cancerous cells originated is referred to as the primary cancer. Metastatic brain tumors are often referred to as brain metastases or lesions. Metastatic brain tumors are the most common brain tumors. Because people are surviving primary cancers for longer periods of time, there has been an
Primary brain tumors originate in the brain itself. Primary brain tumors do not spread from the brain to other parts of the body except in rare cases. Pathologists classify primary brain tumors into two groups: glial tumors (gliomas) and nonglial tumors. Gliomas are composed of glial cells, which include astrocytes, oligodendrocytes, ependymal cells, Schwann cells, microglia, and satellite cells. Nonglial tumors develop on or in structures within the brain, such as nerves, blood vessels, and glands. Metastatic or secondary brain tumors begin as cancer in another part of the body. Some of the cancer cells may be carried to the brain by the blood or may spread from adjacent tissue. The site where the cancerous cells originated is referred to as the primary cancer. Metastatic brain tumors are often referred to as brain metastases or lesions. Metastatic brain tumors are the most common brain tumors.
Primary brain tumors arise in brain tissue, whereas metastatic, or secondary, brain tumors start as cancer cells in another part of the body and metastasize, or spread, to the brain through the blood stream. The most common types of tumors that spread to the brain are lung, breast, colon and kidney cancers, as well as malignant melanoma (skin cancer). Metastatic brain tumors are far more common than primary brain tumors. According to the American Brain Tumor Association, of the 190,000+ Americans diagnosed with a brain tumor each year, slightly more than 40,000 have primary tumors, while the remaining 150,000 have metastatic tumors.
