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Brain tumor - From Wikipedia, the free encyclopedia
A brain tumor is an abnormal growth of cells within the brain or inside the
skull, which can be cancerous or non-cancerous (benign).
It is defined as any intracranial tumor created by abnormal and uncontrolled
cell division, normally either in the brain itself (neurons, glial cells
(astrocytes, oligodendrocytes, ependymal cells), lymphatic tissue, blood
vessels), in the cranial nerves (myelin-producing Schwann cells), in the brain
envelopes (meninges), skull, pituitary and pineal gland, or spread from cancers
primarily located in other organs (metastatic tumors).
Primary (true) brain tumors are commonly located in the posterior cranial fossa
in children and in the anterior two-thirds of the cerebral hemispheres in
adults, although they can affect any part of the brain.
In the United States in the year 2005, it was estimated there were 43,800 new
cases of brain tumors (Central Brain Tumor Registry of the United States,
Primary Brain Tumors in the United States, Statistical Report, 2005–2006),
which accounted for 1.4 percent of all cancers, 2.4 percent of all cancer
deaths, and 20–25 percent of pediatric cancers. Ultimately, it is estimated
there are 13,000 deaths per year in the United States alone as a result of
brain tumors.
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