This aggressive entity found within the context of CMN is due to a different biological behavior with the presence of somatic mutations in 81% of cases in the NRAS gene of the melanocytes, in detriment of the mutations BRAF, demonstrating that they are genetically different from nevi developed after birth and an important risk factor for primary CNS and cutaneous melanoma.4 The gene discussed is NRAS; the disease is congenital mesoblastic nephroma.