Skin cancer - melanoma; Malignant melanoma; Lentigo maligna
Melanoma is caused by changes in skin cells called melanocytes. These cells make a skin color pigment called melanin. Melanin is responsible for skin and hair color.
Melanoma can appear on normal skin. Or, it can begin as a mole or other area that then changes in appearance. Some moles that are present at birth may develop into melanomas.
There are four major types of melanoma:
Superficial spreading melanoma is the most common type. It is usually flat and irregular in shape and color, with different shades of black and brown. It is most common in Caucasians.
Nodular melanoma usually starts as a raised area that is dark blackish-blue or bluish-red. Some do not have any color (amelanotic melanoma).
Lentigo maligna melanoma usually occurs in the elderly. It is most common in sun-damaged skin on the face, neck, and arms. The abnormal skin areas are usually large, flat, and tan with areas of brown.
Acral lentiginous melanoma is the least common form. It usually occurs on the palms, soles, or under the nails. It is more common in African Americans.
In rare cases, melanomas appear in the mouth, iris of the eye, or retina at the back of the eye. These may be found during dental or eye exams. In very rare cases, a melanoma develops in the vagina, esophagus, anus, urinary tract or small intestine.
Melanoma is not as common as other types of skin cancer, such as basal cell cancer. But more and more persons are developing melanoma.
The risk of developing melanoma increases with age, though it can also be seen in young people.
You are more likely to develop melanoma if you:
Have fair skin, blue or green eyes, or red or blond hair
Live in sunny climates or at high altitudes
Spent a lot of time in high levels of strong sunlight because of a job or other activities
Have had one or more blistering sunburns during childhood
Use tanning devices
Other risk factors include:
Close relatives with melanoma
Certain types of moles (atypical or dysplastic) or many birthmarks
Weakened immune system due to disease or medication
A mole, sore, lump, or growth on the skin can be a sign of melanoma or other skin cancer. A sore or growth that bleeds, or changes in color can also be a sign of skin cancer.
The ABCDE system can help you remember possible symptoms of melanoma:
Asymmetry: One half of the abnormal area is different from the other half.
Borders: The edges of the growth are irregular.
Color: Color changes from one area to another, with shades of tan, brown, or black, and sometimes white, red, or blue. A mixture of colors may appear within one sore.
Diameter: The spot is usually (but not always) larger than 6 mm in diameter -- about the size of a pencil eraser.
Evolution: The mole keeps changing appearance.
The key to successfully treating melanoma is recognizing symptoms early. You might not notice a small spot if you do not look carefully. Have yearly skin checks by a dermatologist, and examine your own skin once a month. Use a hand mirror to check hard-to-see places. Call your doctor if you notice anything unusual.
Exams and Tests
Your doctor will check your skin and look at the size, shape, color, and texture of any suspicious areas.
If your doctor thinks you might have skin cancer, a piece of skin from the growth will be removed. This is called a skin biopsy. The sample is sent to a lab for examination under a microscope.
A sentinel lymph node (SLN) biopsy may be done in some people with melanoma to see if the cancer has spread to nearby lymph nodes.
Once melanoma has been diagnosed, CT scans or other types of x-rays may be done to see if the cancer has spread.
Surgery is needed to treat melanoma. The skin cancer and some surrounding area will be removed. How much skin is removed depends on how deep the melanoma has grown.
If the cancer has spread to nearby lymph nodes, these lymph nodes may also be removed. After surgery, you may receive a medicine called interferon.
Treatment is more difficult when the melanoma has spread to other organs. In this case, it usually cannot be cured. Treatment involves shrinking the skin cancer and making you as comfortable as possible. You may receive:
Chemotherapy: Medicines are used to kill cancer cells. It is usually given if the melanoma has returned or spread.
Immunotherapy: Medications such as interferon or interleukin help your immune system fight the cancer. They may be used along with chemotherapy and surgery.
Radiation treatments: These may be used to relieve pain or discomfort caused by cancer that has spread.
Surgery: Surgery may be done to remove cancer that has spread to other parts of the body. This is done to relieve pain or discomfort associated with the growing cancer.
If you have melanoma that is hard to treat, you might consider enrolling in a clinical trial. Ask your doctor for more information. Researchers continue to study new treatments.
You can ease the stress of illness by joining a cancer support group. Sharing with others who have common experiences and problems can help you not feel alone.
How well a patient does depends on many things, including how soon the cancer was diagnosed, and how far it has spread.
If caught early, some melanomas can be cured.
Melanoma that is very deep or has spread to the lymph nodes is more likely to return after treatment. If it is deeper than 4 mm or has spread to the lymph nodes, the cancer is more likely to have spread to other tissues and organs.
Melanoma usually cannot be cured when the cancer has spread beyond the skin and nearby lymph nodes.
If you have had melanoma and recovered, it is very important to examine your body regularly for any unusual changes. Your risk of melanoma increases once you have had this cancer. Melanoma can return years later. Usually, people who have had melanoma are checked by their skin doctor several times a year.
Melanoma can spread to other parts of the body very quickly.
Melanoma treatment can cause side effects, including pain, nausea, and fatigue.
When to Contact a Medical Professional
Call your health care provider if you notice a new growth or any other changes in your skin. You should also call if an existing spot becomes painful, swollen, or inflamed, or if it starts to bleed or itch.
Some people should see a dermatologist for regular skin exams. These include people with:
A family history of melanoma
Severely sun-damaged skin
Lots of moles on their skin
A skin doctor can examine you and tell you whether you need regular skin checks. Sometimes, unusual moles are removed to prevent them from turning into melanoma.
You should also examine your own skin once a month, using a mirror to check hard-to-see places. Call your doctor if you notice any changes.
The best way to prevent skin cancer is to reduce your exposure to sunlight. Ultraviolet light is most intense between 10 a.m. and 4 p.m. Try to avoid sun exposure during these hours. Protect your skin by wearing a hat, long-sleeved shirt, long skirt, or pant when you do have to be outside. The following tips can also help:
Apply high-quality sunscreen with a sun protection factor (SPF) rating of at least 15, even when you are only going outdoors for a short time.
Apply a large amount of sunscreen on all exposed areas, including ears and feet.
Look for sunscreens that block both UVA and UVB light.
Use a waterproof formula.
Apply sunscreen at least 30 minutes before going outside. Reapply it often, especially after swimming.
Use sunscreen in winter, too. Protect yourself even on cloudy days.
Other important facts to help you avoid too much sun exposure:
Avoid surfaces that reflect light more, such as water, sand, concrete, and white-painted areas.
Be extra careful at higher altitudes, where skin burns faster.
Avoid sun lamps, tanning beds, and tanning salons.
Gangadhar TC, Fecher LA, Miller CJ, et al. Melanoma. In: Niederhuber JE, Armitage JO, Doroshow JH, et al, eds. Abeloff's Clinical Oncology. 5th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2013:chap 69.
National Cancer Institute: PDQ Melanoma Treatment. Bethesda, MD: National Cancer Institute. Last modified March 19, 2014. Available at http://cancer.gov/cancertopics/pdq/treatment/melanoma/HealthProfessional. Accessed May 5, 2014.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology. (NCCN Guidelines): Melanoma. Version 4.2014. Available at http://www.nccn.org/professionals/physician_gls/pdf/melanoma.pdf. Accessed May 5, 2014.
Richard J. Moskowitz, MD, Dermatologist in Private Practice, Mineola, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.