MSD Manual

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Quick Facts


(Malignant Melanoma)


The Manual's Editorial Staff

Last full review/revision Oct 2019| Content last modified Oct 2019
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What is melanoma?

Melanoma is a type of skin cancer. It starts in skin cells called melanocytes. Melanocytes make the brown substance that gives skin its color. So melanomas are usually a dark color. The cancer can start in normal skin or in a mole.

  • Melanoma usually starts as a new, small, dark-colored growth on a sun-exposed part of your skin

  • Melanoma can also start in a part of your body that doesn’t get sunlight, like the inside of your mouth

  • The cancer spreads easily to other parts of the body where it destroys tissue and is often fatal

  • To diagnose melanoma, doctors do a biopsy, which is taking out a small sample of the tissue to look at it under a microscope

  • If your melanoma is diagnosed early enough, surgery can usually cure it

Melanoma isn't nearly as common as other skin cancers. However, it's more deadly.

Who is at risk for melanoma?

These risk factors make you more likely to get melanoma:

  • Long-term sun exposure and sunburn

  • Use of tanning beds

  • Family members with melanoma or many moles with different shapes

  • Fair skin and freckles

  • Large number of moles with different shapes or color

What are the symptoms of melanoma?

Melanomas can vary in the way they look. They can be:

  • Flat brown patches with a ragged border and small black spots

  • Raised brown patches with red, white, black, or blue spots

  • Firm red, black, or gray lumps

Melanoma is less common in dark-skinned people. If a dark-skinned person does get melanoma, it's often under the fingernails or toenails or on the palms or soles of the feet.

Symptoms of melanoma are any skin growth that is:

  • Getting bigger

  • Getting darker

  • Inflamed (red and swollen)

  • Spotty and changing color

  • Bleeding, or the skin over it breaks open

  • Itchy, tender, or painful

How can doctors tell if I have melanoma?

Doctors will do a biopsy (cut out a small sample of your tissue to look at under a microscope).

ABCDEs of melanoma

The warning signs of melanoma are sometimes called the ABCDEs of melanoma. The letters ABCDE stand for:

  • Asymmetry: the two halves of the skin growth aren't the same shape

  • Borders: the skin growth has a ragged border or blends into the surrounding skin

  • Color: the skin growth changes color, especially to brown, black, red, white, blue or a color different or darker than your other moles

  • Diameter: the skin growth is wider than a quarter inch (larger than the size of a pencil eraser)

  • Evolution: the skin growth appears when you're more than 30 years old, or has grown or changed recently

How do doctors treat melanoma?

Doctors treat melanoma with surgery by cutting out the skin growth and at least a half inch of skin around the cancer. If surgery isn’t possible, your doctor may give you medicine, try killing the growth with extreme cold (cryotherapy), or give you radiation.

If the melanoma spreads to other parts of your body, your doctor may try:

  • Surgery to take out the cancerous tissue

  • Medicines that help your immune system kill the cancer

  • Medicines that find and kill melanoma cancer cells

How can I prevent melanoma?

You can help prevent melanoma by limiting sun exposure:

  • Stay out of the sun—sit in the shade, try to avoid the sun between 10:00 am and 4:00 pm

  • Don't sunbathe or use tanning beds

  • Wear protective clothing, such as long-sleeved shirts, pants, and hats with broad brims

  • Use sunscreen that’s at least 30 sun protection factor (SPF)—it's important to use more sunscreen every 2 hours and after swimming or sweating

Visit your doctor at least once per year for a skin exam if you:

  • Have had melanoma before

  • Have many moles

See a doctor if you see a change in a skin growth that doesn't go away after a few weeks.

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