Cancer can happen anywhere in the body, even in the blood. A cell that divides out of control can make a clump of cells called a tumor. If a tumor grows in one place in the body, it is sometimes a benign tumor. Benign tumors often don’t need to be treated and can sometimes be left alone.

Tumors that spread quickly to other parts of the body are usually malignant tumors (“cancer”). Malignant tumors are generally more harmful than benign tumors because they can spread throughout the body and can affect your health in many ways.