What Is Melanoma?

Melanoma is the most serious type of skin cancer.

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.

How and where does melanoma appear?

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 men, melanoma most often shows up:
on the upper body, between the shoulders and hips
on the head and neck

In women, melanoma often develops on the lower legs.

In dark-skinned people, melanoma often appears:
under the fingernails or toenails
on the palms of the hands
on the soles of the feet

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.

With early diagnosis and treatment, the chances of recovery are very good.

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.

Glossary

Cancer: A general term for more than 100 different diseases that involve the uncontrolled increase of abnormal new cells. These cells form tumors that can destroy surrounding tissue and spread throughout the body.
Melanin: A dark-brown to black pigment found in the skin, hair, and parts of the eyes.
Melanocytes: Pigment-producing cells located in the epidermis.
Melanoma: A highly malignant type of skin cancer that arises in melanocytes, the cells that produce pigment. Melanoma usually begins in a mole.
Mole: A cluster of melanocytes and surrounding supportive tissue that usually appears as a tan, brown, or flesh-colored spot on the skin. Also called a nevus.
Skin: The outer covering of the body, consisting of an outer layer, the epidermis, an inner layer, the dermis, and a layer of fatty tissue.
Ultraviolet (UV) rays: Invisible rays from the sun. UV radiation can burn the skin and cause melanoma and other types of skin cancer. UV radiation that reaches the earth's surface is made up of two types of rays: UVA and UVB. UVA rays pass deeper into the skin and UVB rays are more likely to cause sunburn. Both kinds of radiation are believed to cause skin cancer and cause premature aging of the skin. People should use sunscreens that block or absorb both kinds of UV radiation.