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Melanoma facts for kids

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Synonyms Malignant melanoma
A melanoma of approximately 2.5 cm (1 in) by 1.5 cm (0.6 in)
Symptoms Mole that is increasing in size, has irregular edges, change in color, itchiness, or skin breakdown.
Causes Ultraviolet light (Sun, tanning devices)
Risk factors Family history, many moles, poor immune function
Diagnostic method Tissue biopsy
Similar conditions Seborrheic keratosis, lentigo, blue nevus, dermatofibroma
Prevention Sunscreen, avoiding UV light
Treatment Surgery
Prognosis Five-year survival rates in US 99% (localized), 25% (disseminated)
Frequency 3.1 million (2015)
Deaths 59,800 (2015)

Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In women, they most commonly occur on the legs, while in men, they most commonly occur on the back. About 25% of melanomas develop from moles. Changes in a mole that can indicate melanoma include an increase in size, irregular edges, change in color, itchiness, or skin breakdown.

The primary cause of melanoma is ultraviolet light (UV) exposure in those with low levels of the skin pigment melanin. The UV light may be from the sun or other sources, such as tanning devices. Those with many moles, a history of affected family members, and poor immune function are at greater risk. A number of rare genetic conditions, such as xeroderma pigmentosum, also increase the risk. Diagnosis is by biopsy and analysis of any skin lesion that has signs of being potentially cancerous.

Using sunscreen and avoiding UV light may prevent melanoma. Treatment is typically removal by surgery. In those with slightly larger cancers, nearby lymph nodes may be tested for spread (metastasis). Most people are cured if spread has not occurred. For those in whom melanoma has spread, immunotherapy, biologic therapy, radiation therapy, or chemotherapy may improve survival. With treatment, the five-year survival rates in the United States are 99% among those with localized disease, 65% when the disease has spread to lymph nodes, and 25% among those with distant spread. The likelihood that melanoma will reoccur or spread depends on its thickness, how fast the cells are dividing, and whether or not the overlying skin has broken down.

Melanoma is the most dangerous type of skin cancer. Globally, in 2012, it newly occurred in 232,000 people. In 2015, 3.1 million people had active disease, which resulted in 59,800 deaths. Australia and New Zealand have the highest rates of melanoma in the world. High rates also occur in Northern Europe and North America, while it is less common in Asia, Africa, and Latin America. In the United States, melanoma occurs about 1.6 times more often in men than women. Melanoma has become more common since the 1960s in areas mostly populated by people of European descent.


Melanomas are usually caused by DNA damage resulting from exposure to UV light from the sun. Genetics also play a role. Melanoma can also occur in skin areas with little sun exposure (i.e. mouth, soles of feet, palms of hands). People with dysplastic nevus syndrome, also known as familial atypical multiple mole melanoma, are at increased risk for the development of melanoma.

Having more than 50 moles indicates an increased risk melanoma might arise. A weakened immune system makes cancer development easier due to the body's weakened ability to fight cancer cells.

UV radiation

The UV radiation from tanning beds increases the risk of melanoma. The International Agency for Research on Cancer finds that tanning beds are "carcinogenic to humans" and that people who begin using tanning devices before the age of thirty years are 75% more likely to develop melanoma.

Those who work in airplanes also appear to have an increased risk, believed to be due to greater exposure to UV.

Having multiple severe sunburns increases the likelihood that future sunburns develop into melanoma due to cumulative damage. The sun and tanning beds are the main sources of UV radiation that increase the risk for melanoma and living close to the equator increases exposure to UV radiation.


A number of rare mutations, which often run in families, greatly increase the risk of melanoma. Several genes increase risks.

Fair- and red-haired people, persons with multiple atypical nevi or dysplastic nevi and persons born with giant congenital melanocytic nevi are at increased risk.

A family history of melanoma greatly increases a person's risk, because mutations in several genes have been found in melanoma-prone families. People with a history of one melanoma are at increased risk of developing a second primary tumor.

Fair skin is the result of having less melanin in the skin, which means less protection from UV radiation exists. A family history could indicate a genetic predisposition to melanoma.

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