The association between having lots of atypical moles all over your body and subsequent melanoma is well established. In a more recent prospective study the risk of moles on the extremities (arms and legs) was specifically looked at. Patients with more than 15 moles on their arms and legs had an almost 3 times risk for melanoma. These melanomas could occur anywhere on the body not just on the extremities, but having more than 15 extremity nevi (moles) identified patients who were at heightened risk.(There was also a small increase risk for basal cell carcinoma also noted but no increase risk of squamous cell cancer in this population). So take close look at your arms and legs and see if you can count to 15, it may be time to get checked!

Citation:

Journal of the American Academy of Dermatology 2019
Extremity Nevus Count Is an Independent Risk Factor for Basal Cell Carcinoma and Melanoma, but Not Squamous Cell Carcinoma
J Am Acad Dermatol 2019 Jan 31;[EPub Ahead of Print], EX Wei, X Li, H Nan