[Nevus and malignant cutaneous melanoma]

Epidemiological studies have revealed that both non-dysplastic benign naevi and dysplastic naevi, as well as large or small congenital naevi are potentially forerunners of malignant skin melanoma (M.S.M.). A studied is presented based on the review of the clinical histories of all the cases of malignant skin melanoma diagnosed (247 cases) by the Dermatology Department of the University Hospital in Valencia from 1977 to 1987. The variables taken into consideration (naevi existing prior to the M.S.M., family history of neoplasias and types of growths, were processed using the SPSS-PC+ statistical package. Forty-two percent of the patients stated the existence of a lesion of the naevi prior to the onset of the malignant skin melanoma (M.S.M.), results differing from those obtained in other series being found which could probably be due to geographical an ethnic characteristics of the different places where said studies were made. With regard to the types of growths, it has been found, with a significance of p less than 0.05, that the malignant nodular melanoma (M.N.M.), the superficial spreading melanoma (S.S.M.) and the unclassifiable melanoma (U.M.) take root more frequently on a naevus than the rest of the growths. Seventy-three percent of the patients had no family history of neoplasias, this suggesting that the onset of this neoplasm was conditioned more by environmental factors (exogenous factors) than by a genetic influence (endogenous factors).