What is skin cancer?: August 2008

Skin moles, which are benign melanocytic lesions, may have occasional cosmetic significance but, for the most part, they are important only in relation to malignant melanoma. skin moles are the most important simulants of malignant melanoma, both clinically and histologically, and can usually be reliably distinguished from malignant melanomas using specific criteria. Some nevi are characterized by greater degrees of atypia and may be more difficult to diagnose. Atypical skin moles are among the most important simulants of malignant melanoma. Skin moles may also be important as potential precursors of malignant melanoma; however, most skin moles are stable and will not progress to malignancy. Skin moles are vastly more common than malignant melanomas and the rate of progression of individual nevi is very low. Therefore, skin moles are not as a rule managed by wholesale excision to prevent malignant melanoma. Skin moles are also important as risk markers, identifying individuals at greater risk of developing malignant melanoma in the future. Atypical skin moles and, to a lesser extent, common acquired and congenital skin moles are among the most important malignant melanoma risk markers. Skin moles of special sites have been identified as skin moles that may show atypical features suggestive of an atypical skin mole or of a malignant melanoma. However, they are not risk markers and they are not malignancies. skin moles of genital skin, acral skin, and flexural skin are among the most important 'skin moles of special sites'. It is important, in considering the differential diagnosis of a nevus in a special site, to avoid overcalling such a nevus as a malignant melanoma or an atypical skin mole because this could lead to excessive treatment. Conversely, it is important to avoid undercalling a nevus that is an atypical skin mole or a malignant melanoma as a skin mole of special sites, because in this circumstance a patient could lose the opportunity either for surveillance to recognize a developing malignant melanoma at an early, curable stage, or for definitive treatment of an established malignancy.