Brain tumors are abnormal growths or masses in the brain. Primary brain cancers arise directly from the cells of the brain. They can be noncancerous or cancerous. The Central Brain Tumor Registry of the United States estimates the occurrence of approximately 63,000 new cases of brain and nervous system tumors among Americans in 2010. Roughly one-third of primary brain and central nervous system tumors are cancerous. In addition to primary brain tumors, cancers from other parts of the body can spread to the brain and cause tumors. These tumors are called metastatic or secondary brain tumors. Metastatic brain tumors are more common than primary brain tumors, especially among adults.
Metastatic Brain Tumors
The National Institute of Neurological Disorders and Stroke reports that approximately 25 percent of all cancers that arise elsewhere in the body spread to the brain, causing metastatic brain tumors. Lung, kidney and breast cancers along with melanomas often spread to the brain causing one or more metastatic brain tumors.
Astrocytomas
Astrocytomas are a common type of brain tumor among adults. They occur less commonly in children. Astrocytomas arise from star-shaped brain cells called astrocytes. These cells support the nerve cells of the brain, providing nutrients and protection. Astrocytomas can be benign or cancerous. The National Cancer Institute reports some types of cancerous astrocytomas are low-grade, meaning they grow slowly. Other types of astrocytomas such as anaplastic astrocytomas and glioblastomas grow quickly and are highly malignant. The UCLA Health System Division of Neurosurgery reports glioblastomas are among the most malignant of all cancers.
Meningiomas
Meningiomas are brain and nervous system tumors that arise from cells forming the protective tissue covering of the brain and spinal cord, the meninges. Meningiomas are a common type of brain tumor among adults. According to the National Cancer Institute, most of these tumors are benign, but cancerous forms do occur.
Medulloblastomas
Medulloblastomas are a common type of brain tumor in children; they rarely occur in adults. According to the UCLA Health System Division of Neurosurgery, these tumors arise from primitive nerve cells. Medulloblastomas occur almost exclusively in an area of the brain called the cerebellum, which controls balance and coordination. The National Cancer Institute states that medulloblastomas are typically high-grade tumors, which grow quickly.
Ependymomas
Ependymomas are a type of brain and nervous system tumor common among children and young adults. These tumors arise from ependymal cells, which line fluid-filled compartments in the center of the brain. These compartments are called the ventricles; they contain spinal fluid. Ependymal cells help produce and circulate spinal fluid. The National Cancer Institute reports that ependymomas can be benign or malignant.
References
- American Cancer Society: Cancer Facts and Figures 2009
- National Cancer Institute: Brain Tumors, Tumor Grades and Types
- National Institute of Neurological Disorders and Stroke: Brain and Spinal Tumors
- Central Brain Tumor Registry of the United States: Fact Sheet
- UCLA Health System, Neurosurgery: Astrocytoma Brain Tumor
