Melanomas don’t always arise from existing moles

In the journals

Published: December, 2017

Image: © Manuel-F-O/Thinkstock

While it's important to have any suspicious mole checked for possible skin cancer, a study published online Aug. 29, 2017, by the Journal of the American Academy of Dermatology suggests most melanomas — the deadliest skin cancer — appear as new spots on the skin. The researchers reviewed 38 studies involving 20,126 cases of melanoma and found that 29% of diagnosed melanomas came from an existing mole, while 71% appeared as new spots. Moreover, they discovered that melanomas that grew from moles were thinner and thus less aggressive than other melanomas. In fact, people whose melanoma was associated with a mole had a better prognosis than others.

The study's authors stressed the importance of looking for any new spots on the skin as well as checking moles for changes, like itching or bleeding, and to see a dermatologist if needed. The American Academy of Dermatology encourages everyone to perform regular skin self-exams, and to ask a partner to check hard-to-see areas like the back. You can learn how to do a skin self-exam, and much more, at

As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.