On the clinical significance of cutaneous melanoma's precursors

We can identify three main groups of cutaneous pigmented lesions that could be represented as melanoma precursors: (a) congenital melanocytic nevi, (b) dysplastic or atypical nevi, and (c) acquired melanocytic nevi. The occurrence of melanoma in small and intermediate congenital melanocytic nevi is very uncommon, but there is a high risk in large congenital melanocytic nevi, in particular those arising in the so-called “bathing trunk” distribution. It is very important to distinguish the familial dysplastic nevus syndrome, which is a strong risk factor for cutaneous melanoma, from not familial (sporadic) dysplastic nevus, in which the risk for melanoma would depend on the total number of melanocytic nevi, phototype, and on the relationship to environmental factors.