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Symptoms
By Mayo Clinic staff
Melanomas can develop anywhere on your body, but they most often develop in areas that have had exposure to the sun, such as your back, legs, arms and face. Melanomas can also occur in areas that don't receive much sun exposure, such as the soles of your feet, palms of your hands and on fingernail beds. These hidden melanomas are more common in people with darker skin.
The first melanoma symptoms often are:
- A change in an existing mole
- The development of a new, unusual-looking growth on your skin
Melanoma doesn't always begin as a mole. It can also occur on otherwise normal-appearing skin.
Normal moles
Normal moles are generally a uniform color, such as tan, brown or black, with a distinct border separating the mole from your surrounding skin. They're oval or round and usually smaller than 1/4 inch (6 millimeters) in diameter — the size of a pencil eraser.
Most people have between 10 and 40 moles. Many of these develop by age 40, although moles may change in appearance over time — some may even disappear with age.
Unusual moles that may indicate melanoma
Characteristics of unusual moles that may indicate melanomas or other skin cancers follow the A-B-C-D-E guide developed by the American Academy of Dermatology:
- A is for asymmetrical shape. Look for moles with irregular shapes, such as two very different-looking halves.
- B is for irregular border. Look for moles with irregular, notched or scalloped borders — characteristics of melanomas.
- C is for changes in color. Look for growths that have many colors or an uneven distribution of color.
- D is for diameter. Look for new growth in a mole larger than about 1/4 inch (6 millimeters).
- E is for evolving. Look for changes over time, such as a mole that grows in size or that changes color or shape. Moles may also evolve to develop new signs and symptoms, such as new itchiness or bleeding.
Other suspicious changes in a mole may include:
- Scaliness
- Itching
- Spreading of pigment from the mole into the surrounding skin
- Oozing or bleeding
Cancerous (malignant) moles vary greatly in appearance. Some may show all of the changes listed above, while others may have only one or two unusual characteristics.
Hidden melanomas
Melanomas can also develop in areas of your body that have little or no exposure to the sun, such as the spaces between your toes and on your palms, soles, scalp or genitals. These are sometimes referred to as hidden melanomas, because they occur in places most people wouldn't think to check. When melanoma occurs in people with darker skin, it's more likely to occur in a hidden area.
Hidden melanomas include:
- Melanoma under a nail. Subungual melanoma is a rare form that occurs under a nail and can affect the hands or the feet. It's more common in blacks and in other people with darker skin pigment. The first indication of a subungual melanoma is usually a brown or black discoloration that's often mistaken for a bruise (hematoma).
- Melanoma in the mouth, digestive tract, urinary tract or vagina. Mucosal melanoma develops in the mucous membrane that lines the nose, mouth, esophagus, anus, urinary tract and vagina. Mucosal melanomas are especially difficult to detect because they can easily be mistaken for other, far more common conditions. A melanoma in a woman's vagina can cause itching and bleeding. Anal melanoma can cause anal bleeding and pain during bowel movements. Melanoma that occurs in the esophagus can cause difficulty swallowing.
- Melanoma in the eye. Eye melanoma, also called ocular melanoma, occurs in the uvea — the layer beneath the white of the eye (sclera). An eye melanoma may cause vision changes and may be diagnosed during an eye exam.
When to see a doctor
Make an appointment with your doctor if you notice any skin changes that seem unusual.
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- Melanoma. Fort Washington, Pa.: National Comprehensive Cancer Network. http://www.nccn.org/professionals/physician_gls/PDF/melanoma.pdf. Accessed April 19, 2010.
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- Yervoy (prescribing information). Princeton, N.J.: Bristol-Myers Squibb; 2011. http://packageinserts.bms.com/pi/pi_yervoy.pdf. Accessed Dec. 19, 2011.
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