The skin is the body's largest organ. It protects against infection and injury, and it helps regulate body temperature. The skin also stores water and fat and produces vitamin D. Melanoma is the most serious form of skin cancer.

Melanoma starts from pigment-producing (color-producing) cells called melanocytes. Frequently, melanoma develops from a pre-existing mole. Melanoma occurs most commonly on the skin of men's backs or on women's legs, but melanoma can occur anywhere on the body, including the head and neck, the skin under the fingernails, and even the soles of the feet or palms of the hands.

The median age at which people are diagnosed with melanoma is just above 50 years old. Still, melanoma occurs in young adults with greater frequency than many other cancer types.

Skin is made up of two main layers: the epidermis (outer layer of skin) and the dermis (inner layer of skin). The deeper layer of the epidermis contains melanocytes. Melanoma can grow deep into the dermis, invading lymph and blood vessels. The initial type of treatment is determined by the thickness of the tumor, and more broadly, by whether the disease has spread (called metastasis) to nearby (regional) lymph nodes or to other parts of the body at the time of diagnosis.

Treatment of the primary (initial) melanoma generally involves surgery, which usually cures early-stage or thin melanoma. Additional surgery may be needed to make sure that the melanoma has been entirely removed and to find out if the melanoma has spread to nearby lymph nodes (tiny, bean-shaped organs that help fight infection). After surgery, the doctor will evaluate whether additional (adjuvant) therapy—such as immunotherapy, chemotherapy, radiation therapy, or further surgery—is necessary. Researchers are also investigating new ways to treat advanced melanoma, including targeted therapies, additional immunotherapies, and vaccine therapy. More details can be found in the Treatment [2] and the Current Research [3] sections.

This section focuses on cutaneous melanoma, which is melanoma that arises on the skin's surface. Melanoma can also develop in the mucous membranes which lines the mouth, gastrointestinal tract, and other locations on the body. Learn more about melanoma diagnosed elsewhere in the body, such as melanoma of the eye [4], melanoma of the anus [5], and melanoma of the vagina [6]. For information on non-melanoma skin cancer, review the section on basal cell and squamous cell skin cancers [7].

Find out more about basic cancer terms used in this section [8].

Looking for More of an Overview?

If you would like additional introductory information, explore these related items on Cancer.Net:

• ASCO Answers Fact Sheet [9]: Read a one-page fact sheet (available in PDF) that offers an easy-to-print introduction for this type of cancer.
• Cancer.Net Patient Education Video [10]: View a short video led by an ASCO expert in this type of cancer that provides basic information and areas of research.

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