Skip Navigation

Visiting Dana-Farber? See our prescreening and mask requirements.

About Melanoma

  • What is melanoma?

    Melanoma is a form of skin cancer that begins and grows in skin cells called melanocytes (cells that make the pigment melanin, which gives skin its color). These are found in the deepest part of the epidermis (the top layer of your skin). The disease typically begins in a mole and can occur anywhere on the body.

    • When caught and treated early, melanoma is a curable disease.
    • Melanoma is a rare form of skin cancer. Unlike most other skin cancers, certain melanomas can invade nearby tissues and spread to other parts of the body.
    • Although more melanomas are being diagnosed, the largest increases are being seen in stage I and early stage II melanomas, which have an excellent prognosis and are generally cured by surgery.
    Anatomy of the skin, showing the epidermis, dermis, and subcutaneous tissue. Melanocytes are in the layer of basal cells at the deepest part of the epidermis.

    Melanoma can occur anywhere on the body

    When melanoma starts in the skin, the disease is called cutaneous melanoma. Melanoma may also occur in mucous membranes (thin, moist layers of tissue that cover surfaces such as the lips). When melanoma occurs in the eye, it is called intraocular or ocular melanoma.

    • In men, it is often on the skin of the head, neck, and trunk.
    • In women, it is often on the legs, but is also common on the trunk and arms.
    • In people with dark skin, it is usually under the fingernails, under the toenails, on the palms, or on the soles of the feet. Melanoma is rare in people with dark skin.


    • The incidence of melanoma is increasing worldwide.
    • Melanoma is most common in adults, but it is sometimes found in children and adolescents. About 300 children in the United States are diagnosed with melanoma each year.
    • Although skin cancer is the most common cancer in the United States, melanoma accounts for less than 2 percent of all skin cancer cases. Basal cell carcinoma and squamous cell carcinoma are more common skin cancers than melanoma.
    • Although the least common type of skin cancer, melanoma is more likely to spread (metastasize) to other parts of the body.

    Growth and spread

    If melanoma grows at the site of the original tumor, it tends to grow in one of two ways:

    • Radial growth: The melanoma spreads horizontally along the top layers of your skin. Most melanomas start growing this way, but some may eventually grow into deeper layers of your skin.
    • Vertical growth: The melanoma grows into deeper layers of skin. This kind of growth is more serious and may spread to other parts of the body. Nodular melanoma grows this way fairly quickly, but most other types grow along the top layers of skin first for some time.

    Risk factors

    Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk with your doctor if you think you may be at risk for melanoma.

    The biggest risk factors for melanoma are:

    • Exposure to natural or artificial sunlight (such as tanning beds) over long periods of time
    • Fair skin that freckles and burns easily, does not tan, or tans poorly
    • Having unusual moles

    Other risk factors for melanoma include:

    • Family history or a personal history of melanoma
    • Ultraviolet radiation (especially from tanning booths)
    • Frequent sunburns (especially blistering sunburns)
    • Number of moles (more than 50)
    • Atypical nevi (unusual moles)
    • Immunosuppression
    • Blue or green or other light-colored eyes
    • Red or blond hair

    Symptoms and signs

    Melanoma can vary greatly in appearance. The most important clue in detecting melanoma is a lesion (abnormal lump, bump, ulcer, sore, or colored area on the skin) that is changing and is unlike any other lesion on your skin.

    Melanoma often starts with a change in the shape, color, size, or texture of an existing mole or a change in how a pigmented area looks. It may also appear as a new mole. Although melanoma is typically a brown/black color, less commonly, it may appear as a pink, fast-growing, shiny bump.

    Normal mole / melanoma Sign Characteristic
    moles - asymmetry Asymmetry When half of the mole does not match the other half
    moles - border Border When the border (edges) of the mole are ragged or irregular
    moles - color Color When the color of the mole varies throughout
    moles - diameter Diameter If the mole's diameter is larger than a pencil's eraser
    Photographs used by permission: National Cancer Institute

    These and other signs and symptoms may be caused by melanoma or by other conditions. Check with your doctor if you have a mole that:

    • Changes in size, shape, or color.
    • Has irregular edges or borders.
    • Is more than one color.
    • Is asymmetrical (if the mole is divided in half, the two halves are different in size or shape).
    • Itches.
    • Oozes, bleeds, or is ulcerated (a hole forms in the skin when the top layer of cells breaks down and the tissue shows through).

    Experts recommend using the "ABCDE rule" to help determine when a physician should see a mole or skin change:

    • A for asymmetry: One half is differently shaped than the other
    • B for border irregularity: Jagged or blurred edges
    • C for color: The pigmentation is not consistent
    • D for diameter: Moles greater than six millimeters (the size of a pencil eraser)
    • E for evolving: A mole changing in size, shape, or color

    Screening and prevention

    The Center for Melanoma Oncology aims to raise awareness, provide risk assessment, and promote healthful behaviors. Dana-Farber's Sun Safety/Skin Cancer Prevention Program regularly visits local beaches and outdoor recreation areas in the summer to conduct skin cancer screenings and sun safety education programs. And Dana-Farber's Center for Cancer Genetics and Prevention offers genetic counseling services to determine an individual's risk of developing melanoma or having a hereditary form of the disease.

    Screening recommendations

    Ages 18+: You should conduct monthly self-exams to look for new moles and birthmarks, or changes in existing ones. Your physician should evaluate them during your annual exam. If you have a large number of moles, atypical moles, or a family history of melanoma, you should have an evaluation by a dermatologist.

    Related links

    Read our Insight blog for information and inspiration about Dana-Farber's approach to the treatment of melanoma.