Mapping Moles and Melanomas: Do Melanomas Mostly Arise in Moles?

Moles are not full stops Nor commas They may lie But sometimes they tell the truth Naevus interruptus

~ From the poem “Moles” (“De Natura Melanoma”: poems by Sharad P. Paul, Middle Island Press 2015)

Everywhere we look there is an advertisement for a clinic that wants to “map’ your moles – the theory being that if we took photos of our moles and then compared these photos every few months we would pick moles that would become melanomas.

In our clinic, we recommend an annual full skin examination. While we have the ability and technology to photograph or “map” moles, we reserve it for particular cases and do not do this on all patients. In patients who have had melanomas, or those with a high-risk we review patients 6 monthly as per guidelines.

In theory taking a map of moles and following them seems a good idea. But the science suggests otherwise. Contrary to commonly held views among the public (and doctors who don’t specialise in skin) only a minority of moles arise from pre-existing moles. Therefore, mapping moles may not be useful as having an annual skin examination. After all, many moles that change are the bumpy harmless ones anyway.

Caterina Longo, MD, PhD, University of Modena and Reggio Emilia, Italy published a study on August 29, 2017 in the Journal of the American Academy of Dermatology. She was quoted as saying, “"It's extremely important to be aware that the majority of melanomas arise de novo because it implies that any newly appearing lesion in adults should be regarded as suspicious.” The study showed that in this series, 29.1% of melanomas were associated with a pre-existing mole; therefore, greater than 70% of the melanomas were not associated with moles. Therefore, mapping all your moles may help but it is better to have an annual skin examination.

We have been at the forefront of skin cancer academia and research for over two decades, and have noted research trends. That’s why when you come to our Skin Surgery Clinic you get a skin examination and not a “mole-map.”

Source: Pam Harrison. Medscape News. Most Melanomas Not Malignant Transformation of Moles - Medscape - Aug 29, 2017.

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