Brain Cancer Overview
Cancers of the brain are the consequence of abnormal growths of cells in the brain. Brain cancers can arise from primary brain cells, the cells that form other brain components (for example, membranes, blood vessels), or from the growth of cancer cells that develop in other organs and that have spread to the brain by the bloodstream (metastatic or secondary brain cancer).
- Although many growths in the brain are popularly called brain tumors, not all brain tumors are cancerous. A tumor is simply a mass of cells. A benign tumor is composed of cells which are not cancerous. A malignant tumor is comprised of cancer cells. Cancer is a term reserved for malignant tumors. Malignant tumors are composed of aggressively growing, abnormal-appearing cells referred to as cancer cells.
- Malignant tumors grow and spread aggressively, invading and spreading into areas of healthy tissue, and then overpowering them by taking their space, blood, and nutrients. Like all cells of the body, tumor cells need blood and nutrients to survive. This is especially a problem in the brain, as the expanding mass caused by added growth within the closed confines of the skull can lead to an increase in pressure within the space inside the skull (intracranial pressure) or the distortion of areas of the brain, causing them to fail to work properly. Both malignant and benign brain tumors can cause the problem of increased intracranial pressure and its consequences. Malignant brain tumors usually cause such problems more aggressively and quickly than do benign brain tumors.
- Almost all tumors that begin in the brain do not spread to other parts of the body. Another major difference between benign and malignant tumors is that while malignant tumors can invade the brain tissues and grow rapidly, benign tumors usually push on, rather than invade, adjacent tissues.
- In general, a benign tumor is less serious than a malignant tumor. However, a benign tumor can still cause many problems in the brain, but usually the problems progress at a slower rate than malignant tumors.
Sometimes people confuse brain aneurysms with brain tumors. Brain aneurysms are not tumors; they are areas in the brain arteries or veins that are abnormally weak and expand to form a ballooning or expansion of the vessel wall. They seldom produce any symptoms unless they begin to leak blood into the surrounding brain tissue or if they burst. Aneurysms may be congenital (present at birth) or expanded or formed in brain vessels after vessel damage (for example, trauma, atherosclerosis, high blood pressure) but are not formed from cancer cells. Unfortunately, when aneurysms produce symptoms, they can resemble those produced by brain tumors.
Medically Reviewed by a Doctor on 4/10/2015
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