[From dysplastic nevus to malignant melanoma--a study of 4 anatomoclinical cases of dysplastic nevus syndrome].

Malignant melanoma (MM) is a skin neoplasm with an increasing incidence. Late discovery is often associated with lethal outcome. Among the possible precursor lesions of MM, the Dysplastic Naevus (DN) is a matter of controversy. We have studied 4 cases of Dysplastic Naevus Syndrome (DNS) and analysed 39 lesions of Dysplastic Naevus. We adopt the "ABCDE" rule (A = Asymmetry, B = Border irregularity, C = Colour inhomogeneity, D = Diameter > 0.5 cm, E = Elevation or Extension) for clinical diagnosis of DN or MM. We conclude that the DN is a risk marker, a precursor of MM and a potential precancerosis. We present recommendations for management of the Dysplastic Naevus Syndrome and prevention of malignant melanoma.