Brain tumors can be benign or malignant:

•       Benign brain tumors do not contain cancer cells:

•        Usually, benign tumors can be removed, and they seldom grow back.

•        The border or edge of a benign brain tumor can be clearly seen. Cells from benign tumors do not invade tissues around them or spread to other parts of the body. However, benign tumors can press on sensitive areas of the brain and cause serious health problems.

•        Unlike benign tumors in most other parts of the body, benign brain tumors are sometimes life threatening.

•        Very rarely, a benign brain tumor may become malignant.

•       Malignant brain tumors contain cancer cells:

•        Malignant brain tumors are generally more serious and often are life threatening.

•        They are likely to grow rapidly and crowd or invade the surrounding healthy brain tissue.

•        Very rarely, cancer cells may break away from a malignant brain tumor and spread to other parts of the brain, to the spinal cord, or even to other parts of the body. The spread of cancer is called metastasis.

Sometimes, a malignant tumor does not extend into healthy tissue. The tumor may be contained within a layer of tissue. Or the bones of the skull or another structure in the head may confine it. This kind of tumor is called encapsulated.