Anevusis a benign (noncancerous) melanocytic tumor, more commonly called amole. Nevi (the plural of nevus) are not usually present at birth but begin to appear in children and teenagers.Most moles will never cause any problems, but a person who has 50 or more moles is more likely to develop melanoma, the most aggressive form ofskin cancer.
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What Is Skin Cancer?
Skin cancer—the abnormal growth of skin cells—most often develops on skin exposed to the sun. But this common form of cancer can also occur on areas of your skin not ordinarily exposed to sunlight. There are three major types of skin cancer—basal cell carcinoma, squamous cell carcinoma, and melanoma. Early detection of skin cancer gives you the greatest chance for successful skin cancer treatment.
Causes of Skin Cancer
Melanoma occurs when something goes awry in the melanin-producing cells (melanocytes) that give color to your skin.
Normally, skin cells develop in a controlled and orderly way—healthy new cells push older cells toward your skin’s surface, where they die and eventually fall off. But when some cells develop DNA damage, new cells may begin to grow out of control and can eventually form a mass of cancerous cells.
Just what damages DNA in skin cells and how this leads to melanoma isn’t clear. It’s likely that a combination of factors, including environmental and genetic factors, causes melanoma. Still, healthcare providers believe exposure to ultraviolet (UV) radiation from the sun and from tanning lamps and beds is the leading cause of melanoma.
UV light doesn’t cause all melanomas, especially those that occur in places on your body that don’t receive exposure to sunlight. This indicates that other factors may contribute to your risk of melanoma.
Skin Cancer Screening
You and your healthcare provider may consider screening options such as:
Types of Nevi
There are multipletypes of nevi. Adysplastic (or “atypical”) nevusis a large, irregularly-shaped type that particularly increases a person’srisk of melanoma: About 50% of melanoma cases occur in people who have dysplastic nevi. People with this condition should speak with adermatologistabout how often to have a thorough skin exam.
Moles usually appear late in childhood, but some are present at birth in those with a condition called “congenital melanocytic nevi.” The lifetime risk of getting melanoma for people with congenital melanocytic nevi has been estimated to be up to 5%, depending on the size of the nevus.
8 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.Common moles, dysplastic nevi, and risk of melanoma.Bhatt M, Nabatian A, Kriegel D, Khorasani H.Does an increased number of moles correlate to a higher risk of melanoma?.Melanoma Manag. 2016;3(2):85-87. doi:10.2217/mmt-2016-0001National Cancer Institute.Skin cancer prevention (PDQ)—patient version.Emri G, Paragh G, Tósaki Á, et al.Ultraviolet radiation-mediated development of cutaneous melanoma: an update.J Photochem Photobiol B. 2018;185:169-175. doi:10.1016/j.jphotobiol.2018.06.005US Preventive Services Task Force, Mangione CM, Barry MJ, et al.Screening for skin cancer: US Preventive Services Task Force Recommendation Statement.JAMA. 2023;329(15):1290-1295. doi:10.1001/jama.2023.4342National Cancer Institute.Skin cancer screening (PDQ)—health professional version.Tan SY, Strazzulla LC, Li X, Park JJ, Lee SJ, Kim CC.Association of clinicopathological features of melanoma with total naevus count and a history of dysplastic naevi: a cross-sectional retrospective study within an academic centre.Clin Exp Dermatol. 2018;43(5):566-572. doi:10.1111/ced.13393National Cancer Institute.Risk factors for melanoma skin cancer.
8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.Common moles, dysplastic nevi, and risk of melanoma.Bhatt M, Nabatian A, Kriegel D, Khorasani H.Does an increased number of moles correlate to a higher risk of melanoma?.Melanoma Manag. 2016;3(2):85-87. doi:10.2217/mmt-2016-0001National Cancer Institute.Skin cancer prevention (PDQ)—patient version.Emri G, Paragh G, Tósaki Á, et al.Ultraviolet radiation-mediated development of cutaneous melanoma: an update.J Photochem Photobiol B. 2018;185:169-175. doi:10.1016/j.jphotobiol.2018.06.005US Preventive Services Task Force, Mangione CM, Barry MJ, et al.Screening for skin cancer: US Preventive Services Task Force Recommendation Statement.JAMA. 2023;329(15):1290-1295. doi:10.1001/jama.2023.4342National Cancer Institute.Skin cancer screening (PDQ)—health professional version.Tan SY, Strazzulla LC, Li X, Park JJ, Lee SJ, Kim CC.Association of clinicopathological features of melanoma with total naevus count and a history of dysplastic naevi: a cross-sectional retrospective study within an academic centre.Clin Exp Dermatol. 2018;43(5):566-572. doi:10.1111/ced.13393National Cancer Institute.Risk factors for melanoma skin cancer.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Cancer Institute.Common moles, dysplastic nevi, and risk of melanoma.Bhatt M, Nabatian A, Kriegel D, Khorasani H.Does an increased number of moles correlate to a higher risk of melanoma?.Melanoma Manag. 2016;3(2):85-87. doi:10.2217/mmt-2016-0001National Cancer Institute.Skin cancer prevention (PDQ)—patient version.Emri G, Paragh G, Tósaki Á, et al.Ultraviolet radiation-mediated development of cutaneous melanoma: an update.J Photochem Photobiol B. 2018;185:169-175. doi:10.1016/j.jphotobiol.2018.06.005US Preventive Services Task Force, Mangione CM, Barry MJ, et al.Screening for skin cancer: US Preventive Services Task Force Recommendation Statement.JAMA. 2023;329(15):1290-1295. doi:10.1001/jama.2023.4342National Cancer Institute.Skin cancer screening (PDQ)—health professional version.Tan SY, Strazzulla LC, Li X, Park JJ, Lee SJ, Kim CC.Association of clinicopathological features of melanoma with total naevus count and a history of dysplastic naevi: a cross-sectional retrospective study within an academic centre.Clin Exp Dermatol. 2018;43(5):566-572. doi:10.1111/ced.13393National Cancer Institute.Risk factors for melanoma skin cancer.
National Cancer Institute.Common moles, dysplastic nevi, and risk of melanoma.
Bhatt M, Nabatian A, Kriegel D, Khorasani H.Does an increased number of moles correlate to a higher risk of melanoma?.Melanoma Manag. 2016;3(2):85-87. doi:10.2217/mmt-2016-0001
National Cancer Institute.Skin cancer prevention (PDQ)—patient version.
Emri G, Paragh G, Tósaki Á, et al.Ultraviolet radiation-mediated development of cutaneous melanoma: an update.J Photochem Photobiol B. 2018;185:169-175. doi:10.1016/j.jphotobiol.2018.06.005
US Preventive Services Task Force, Mangione CM, Barry MJ, et al.Screening for skin cancer: US Preventive Services Task Force Recommendation Statement.JAMA. 2023;329(15):1290-1295. doi:10.1001/jama.2023.4342
National Cancer Institute.Skin cancer screening (PDQ)—health professional version.
Tan SY, Strazzulla LC, Li X, Park JJ, Lee SJ, Kim CC.Association of clinicopathological features of melanoma with total naevus count and a history of dysplastic naevi: a cross-sectional retrospective study within an academic centre.Clin Exp Dermatol. 2018;43(5):566-572. doi:10.1111/ced.13393
National Cancer Institute.Risk factors for melanoma skin cancer.
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