Melanoma is the most serious type of skin cancer. It begins in skin cells called melanocytes. Though melanoma is predominantly found on the skin, it can even occur in the eye (uveal melanoma).
Melanocytes are the cells that make melanin, which gives skin its color. Melanin also protects the deeper layers of the skin from the sun's harmful ultraviolet (UV) rays.
When people spend time in the sunlight, the melanocytes make more melanin and cause the skin to tan. This also happens when skin is exposed to other forms of ultraviolet light (such as in a tanning booth). If the skin receives too much ultraviolet light, the melanocytes may begin to grow abnormally and become cancerous. This condition is called melanoma.
The first sign of melanoma is often a change in the size, shape, or color of a mole. But melanoma can also appear on the body as a new mole.
In women, melanoma often develops on the lower legs.
Although these are the most common places on the body for melanomas to appear, they can appear anywhere on the skin. That's why it is important to always examine your skin to check for new moles or changes in moles.
The chance of getting melanoma increases as you get older, but people of any age can get melanoma. In fact, melanoma is one of the most common cancers in young adults (ages 25 to 29). Each year, more than 50,000 people in the U.S. learn that they have melanoma.
Melanoma is a serious and sometimes life-threatening cancer. If melanoma is found and treated in its early stages, the chances of recovery are very good. If it is not found early, melanoma can grow deeper into the skin and spread to other parts of the body. This spread is called metastasis.
Once melanoma has spread to other parts of the body beyond the skin, it is difficult to treat.