SUN EXPOSURE AND LARGE NUMBERS OF COMMON AND ATYPICAL MELANOCYTIC NEVI - AN ANALYTICAL STUDY IN A SOUTHERN EUROPEAN POPULATION

The study analysed the relationship between high counts of common naev i and numbers of atypical naevi (AN) in sites differing in exposure to the sun. A series of 90 subjects with 100 or more common naevi (cases ) and 92 controls was investigated by means of a case-control study. A striking association between high numbers of common naevi and prevale nce of AN (whole body) was found. The adjustment for phenotype and pho totype did not obscure this association. Similar findings were obtaine d after exclusion of subjects with familiarity for melanoma. Cases had more AN than controls in all the body sites, except for the buttocks. where sun exposure call be considered minimal or absent: in this site , an excess of common naevi but not of AN was found. The present study suggests that subjects with high common naevi counts show a higher pr evalence of AN independently of their complexion, sunburn history and family history of melanoma. Phenotypic expression of AN seems to be en hanced by direct sun exposure.