Melanoma is a type of skin cancer. It is an aggressive skin cancer that can spread to other parts of the body. The incidence of melanoma has been increasing over the last several decades.

What is going on in the body?

Melanocytes are pigment cells that are usually found in the skin. They produce melanin, which is the pigment that gives skin its color. Clusters of melanocytes and surrounding skin sometimes form moles. Moles are benign, or noncancerous, growths. Most people have between 10 to 40 moles on their skin. Moles may be brown, pink, or tan. Moles may be flat or raised and are usually round or oval.

Melanoma, on the other hand, is a cancerous growth. It occurs when pigment cells become malignant, divide without control, and invade the tissue around them. Melanoma is usually found on visible skin but can also occur inside the eye or around the anus. This kind of skin cancer is very aggressive. Cancer cells from the tumor may enter the blood stream. They also may enter the lymphatic system, which has tissues and organs that make and store cells to fight infection. Cancer can spread to another part of the body and form new destructive tumors. This spread of the disease is called metastasis.

What are the causes and risks of the disease?

Melanoma is strongly related to sun exposure. The incidence of melanoma has increased as people spend more and more recreational time in the sun. A history of blistering sunburns in childhood may significantly raise the risk of melanoma.

Other risk factors that increase a person's risk for melanoma are:

The peak incidence of melanoma occurs between ages 20 and 45.