The National Cancer Institute estimated that in 2011, doctors will diagnose 22,340 new cases of brain tumors, and an estimated 13,110 people will also pass away because of a brain tumor. The idea of a brain tumor can be frightening — an abnormal mass of cells are in the brain, either having originated in the brain or from elsewhere in the body.
But does having a brain tumor mean you have cancer? Do brain tumors affect different cells? This brain tumors overview will answer those questions.
What is a brain tumor?
Simply, a brain tumor is made up of an abnormal growth of tissue. Some brain tumors start in the brain. These brain tumors are called primary brain tumors.
But in some cases, the abnormal tissue starts elsewhere in the body and spreads to the brain. These brain tumors are called metastatic brain tumors or secondary brain tumors.
With a metastatic brain tumor, the abnormal tissue travels up to the brain through the bloodstream and the lymph system. MedlinePlus noted that metastatic brain tumors are more common than primary brain tumors. Between 10 and 30 percent of adult cancer patients have a metastatic brain tumor.
Certain cancers have a higher likelihood of resulting in a metastatic brain tumor. Examples include melanoma, breast cancer, colon cancer, lung cancer and nasopharyngeal cancer, according to the Ohio State University Medical Center.
Are all brain tumors cancerous?
No, some types of brain tumors are benign, in that they do not contain cancerous cells. The Ohio State University explained that the majority of benign brain tumors have clear borders, which means that unlike malignant or cancerous brain tumors, they do not invade healthy surrounding tissue.
An example is a meningioma, which MedlinePlus noted is 90 percent of the time benign. Meningiomas occur in the meninges, which are the membranes that cover the spinal cord and brain. While benign brain tumors are not cancerous, they can cause serious symptoms depending on where in the brain they are located and how big they are.
Do brain tumors affect different cells in the brain?
The names of the different brain tumors come from what cells in the brain they affect. For example, the group of brain tumors called gliomas affects the glial cells, which are the supportive cells in the brain. The brain has about 100 billion neurons, or nerve cells, the University for Washington noted that the number of glial cells may be 10 to 50 times greater.
Astrocytomas and glioblastomas come from the glial cells called astrocytes. Other examples include ependymomas, which arise from ependymal cells and pineoblastomas, which arise the pineal gland cells.
References
National Cancer Institute. Brain Tumor Home Page. Web. 19 September 2011
http://www.cancer.gov/cancertopics/types/brain
The Ohio State University Medical Center. Brain Tumors. Web. 19 September 2011
http://medicalcenter.osu.edu/patientcare/healthcare_services/nervous_system/tumors/pages/index.aspx
University of Washington. Glia. Web. 19 September 2011
http://faculty.washington.edu/chudler/glia.html
MayoClinic.com. Brain Tumor. Web. 19 September 2011
http://www.mayoclinic.com/health/brain-tumor/DS00281/METHOD=print
MedlinePlus Medical Encyclopedia. Metastatic Brain Tumor. Web. 19 September 2011
http://www.nlm.nih.gov/medlineplus/ency/article/000769.htm
MedlinePlus Medical Encyclopedia. Brain Tumor – Primary – Adults. Web. 19 September 2011
http://www.nlm.nih.gov/medlineplus/ency/article/007222.htm
MedlinePlus Medical Encyclopedia. Brain Tumor – Children. Web. 19 September 2011
http://www.nlm.nih.gov/medlineplus/ency/article/000768.htm
Reviewed September 19, 2011
by Michele Blacksberg RN
Edited by Jody Smith