Moles are brown or black growths, usually round or oval, that can appear anywhere on the skin. They can be rough or smooth, flat or raised, single or in multiples. They occur when cells that are responsible for skin pigmentation, known as melanocytes, grow in clusters instead of being spread out across the skin. Generally, moles are less than one-quarter inch in size. Most moles appear by the age of 20, although some moles may appear later in life. Most adults have between 10 and 40 moles. Because they last about 50 years, moles may disappear by themselves over time.
Most moles are harmless, but a change in size, shape, color or texture could be indicative of a cancerous growth. Moles that have a higher-than-average chance of becoming cancerous include:
Moles present at birth. The larger their size, the greater the risk for developing into a skin cancer.
Atypical Dysplastic Nevi
Irregularly shaped moles that are larger than average. They often appear to have dark brown centers with light, uneven borders.
Higher frequency of moles
People with 50 or more moles are at a greater risk for developing a skin cancer.
In some cases, abnormal moles may become painful, itchy, scaly or bleed. It’s important to keep an eye on your moles so that you can catch any changes early. We recommend doing a visual check of your body monthly, including all areas that don’t have sun exposure (such as the scalp, armpits or bottoms of feet).
Use the American Academy of Dermatology’s ABCDEs as a guide for assessing whether or not a mole may be becoming cancerous:
Asymmetry: Half the mole does not match the other half in size, shape or color.
Border: The edges of moles are irregular, scalloped, or poorly defined.
Color: The mole is not the same color throughout.
Diameter: The mole is usually greater than 6 millimeters when diagnosed, but may also be smaller.
Evolving: A mole or skin lesion that is different from the rest, or changes in size, shape, or color.