What is a brain tumor? A brain tumor is an abnormal growth of
tissue in the brain. The tumor can either originate in the brain
itself (primary brain tumor), or come from another part of the
body and travel to the brain (metastatic or secondary tumor).
Brain tumors may be classified as either benign (noncancerous)
or malignant (cancerous), depending on their behavior. A benign
tumor does not contain cancer cells and usually, once removed,
does not recur. Most benign brain tumors have clear borders,
meaning they do not invade surrounding tissue. These tumors can,
however, cause symptoms similar to cancerous tumors because of
their size and location in the brain. Malignant brain tumors
contain cancer cells. Malignant brain tumors are usually fast
growing and invade surrounding tissue. Malignant brain tumors
very rarely spread to other areas of the body, but may recur
after treatment. Sometimes, brain tumors that are not cancer are
called malignant because of their size and location, and the
damage they can do to