Giant melanocytic nevus may be explained as a superimposed patchy manifestation of a polygenic trait.

Cases of GMN associated with small disseminated nevi involving the entire body have been documented with historical figures published in many articles and textbooks [4–9] and have also been reported in more recent publications [10–13] . So far, the associated small nevi have usually been categorized as ‘satellite lesions’ [4, 12, 13] . Admittedly, true satellite lesions are often noted. As a rule of thumb, such satellite nevi tend to be found within a 15-cm zone surrounding a GMN, which is reminiscent of an archipelago. By contrast, a scattered distribution all over the body ( fig. 1 , 2 ) suggests that in such cases the associated small nevi should rather be taken as disseminated ‘background lesions’. These common small melanocytic nevi do not mendelize but represent a polygenic trait [14–16] . Specifically, recent molecular research has shown that both congenital and acquired small melanocytic nevi have a common polygenic background, including mutations at the loci of BRAF, N-ras, MC1R and p53 [17–20] .