Skin cancer is a disease in which skin cells grow abnormally. In healthy skin new cells develop all the time to replace older cells. These normal new cells multiply and grow in an orderly way.
If skin cells grow out of control they form a mass or ‘tumor’.
A skin tumor is considered benign (not cancer) if it is limited to a few cell layers and does not invade surrounding tissues or organs. But if the tumor spreads to surrounding tissues it is considered malignant or cancerous.
Most skin growths are benign (not harmful).
There are 3 different types of skin cancer. They are different because they arise from one of the 3 different types of cells in the outer layer of the skin (see below to read about the different types of cells).
Each kind of skin cancer has its own distinctive appearance. Certain skin cancers also tend to develop in specific areas of the body.