Histological examination of 1101 melanomas (990 superficial spreading and 111 nodular melanomas) from 1098 people revealed that 23.3% showed an associated melanocytic naevus. Of these, 56.5% were classified histologically as common acquired, 37.7% as dysplastic and 5.8% as congenital. Of the superficial spreading melanomas, 25.7% showed an associated naevus. By contrast, only 2.7% of nodular melanomas showed histological evidence of a coexisting naevus. When the superficial spreading melanomas were analysed by level, the presence of a naevus varied from 31.3% of level I melanomas to 21.3% of level IV melanomas. When thickness was measured, an associated naevus was found in 27.0% of superficial spreading melanomas less than 1.0 mm thick, and 14.8% of melanomas with a thickness of 1.0 mm or greater. These data suggest that most melanomas do not arise in pre-existing naevi, and accordingly public educational programs for the early detection of melanoma should focus on looking for changes in previously normal skin as well as in pre-existing moles.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.