UMM is genetically distinct from cutaneous melanoma (CM): while CM cells carry mutation of BRAF, NRAS or KIT genes, UMM cells carry activating mutations in the G protein-coupled receptor (GPCR) pathway alpha subunits GNAQ or GNA11 [4,5] and inactivating somatic mutations in gene encoding for BRCA-1-associated protein 1 (BAP1) [4,5]. This evidence concerns the gene NRAS and cutaneous mastocytosis.