—Lizette G., University of the District of Columbia, Washington DC
Yes. It’s very common for people to acquire and lose moles over the course of their lifetime. Mole accumulation peaks in the 30s and after that, the overall number of moles tends to decline with time.
A mole is a cluster of pigment-producing cells in the skin. They can be deeper (in the dermal layer), more superficial (at the junction between the dermal layer and epidermis), or a combination of these. The superficial moles tend to be more raised above the skin surface.
Are all moles the same?
No. The two major categories are “common acquired melanocytic nevi” and “atypical nevi.” The first type meets all the criteria of benign (non-cancerous) lesions—see ABCDE below. Atypical nevi share some appearance characteristics with melanoma. Moles occur more on sun-exposed parts of the body. People with more moles are at a greater risk of developing melanoma.
Where do moles come from?
Mommy and Daddy moles!
Just kidding. There are three factors that increase the likelihood of developing most types of moles: genetics, degree of childhood sun exposure (especially intense and intermittent sun exposure), and overall pigmentation levels. Caucasians are much more likely to develop moles than are darker-skinned people.
I’m supposed to worry about skin cancer when I find a mole, right?
Yes and no. Most moles are benign (not cancerous) and not likely to become cancer. However, some moles are worthy of further evaluation. To check your moles, follow the “ABCDE” evaluation below (and visit melanoma.org):
Asymmetry: Benign moles are usually symmetrical. Melanoma lesions, which can become cancerous, are often irregular, or not symmetrical, in shape.
Border: Typically, non-cancerous moles have smooth, even borders. Melanoma lesions usually have irregular borders that are difficult to define.
Color: Benign moles are usually a single shade of brown or tan. The presence of more than one color (blue, black, brown, tan, etc.) or the uneven distribution of color can sometimes be a warning sign of melanoma.
Diameter: Melanoma lesions are often greater than six millimeters in diameter (approximately the size of a pencil eraser).
Evolution: The evolution of your mole(s) is the most important factor to consider when it comes to diagnosing a melanoma. Knowing what’s normal for you could save your life. If a mole has gone through recent changes in color and/or size, bring it to the attention of a dermatologist immediately.
If you have a new or changing mole, especially one that meets any of the criteria for concern above, it’s a good idea to have it evaluated by a qualified medical practitioner. They may perform a biopsy (removal of a sample of the skin) to evaluate the mole microscopically and perform other testing. Melanoma is a type of skin cancer that can initially look like a mole. While rare in young people—0.4 percent of cases occur in those under age 20—early detection is super important for good outcomes for people of any age. People with a large number of moles, especially on the back or other areas that are hard to monitor, should probably see a dermatologist.
Should I have all my moles removed just in case?
No. Research has not found that removing benign moles decreases risk of melanoma.
Do moles ever go away?
Yes. Some of them do go away sometimes. This change is sometimes foreshadowed by the development of an unpigmented ring around the mole. It can take up to 10 years for the mole to go away and the skin pigmentation to normalize.
Is there any location for a mole to appear that is definitely always abnormal?
No. Benign (non-cancerous) moles can develop almost anywhere on the body, such as under nails, on the scalp, on the palms or soles, and on the face.
How can I prevent skin cancer?
Some factors, like our genetic makeup, are not changeable. However, other factors, like UV exposure, are. By limiting overexposure to the sun, we can significantly decrease the risk of later developing skin cancer, including melanoma.