Skin cancer, like cancer in other organs of the body, is the result of the uncontrolled, abnormal growth of cells. Cells are the tiny, individual units of all organs in our body, and they are responsible for the normal activity that keeps us healthy. When the cells in the skin begin to grow in an uncontrolled, abnormal fashion, a tumor will result. This tumor may be benign or malignant.

A malignant tumor is considered a cancer and should be removed to prevent the possibility of invasion and destruction of surrounding normal tissue, or the spread of the cancer to other organs in the body. This is known as a metastasis. Fortunately, metastasis of skin cancer is not common. Skin cancers, however, frequently invade surrounding normal tissue causing extensive destruction of skin and body structures. Benign tumors do not metastasize and, in general, do not cause harm to a patient if they are not removed.