Nevus anemicus and RASopathies

Abstract

Tadini and colleagues were the first to report the correlation between anemic nevi and RASopathies.1 A retrospective study in their genodermatosis center identified anemic nevi at different anatomic sites in a cohort of neurofibromatosis type 1 (NF1) (50/565). In 2013, Marque et al published the frequent occurrence of anemic nevi in 77 of 151 patients clinically diagnosed with NF1, but not in 7 patients with SPRED1 (sprouty-related, EVH1 domain–containing protein 1), 2 with PTPN11 (protein tyrosine phosphatase nonreceptor type 11), and 1 with RAF1 (rapidly accelerated fibrosarcoma-1) mutations.2 In a later study in 100 genetically confirmed NF1 patients, anemic nevi were found in 28 children with NF1,3 much higher than the estimated 1%-5% in the general population.2 Anemic nevi were suggested as an additional diagnostic marker of NF1, facilitating differentiation from other genodermatoses with cafe au lait macules (CALMs) and lentigines.1, 2, 3 Anemic nevi are congenital pale macules or patches, which become more prominent by warming or rubbing of the skin and disappear with diascopy or wood lamp examination.1, 2 In a review of the clinical features of 159 patients with Legius syndrome (LS), anemic nevi were not reported4; however, they can easily be overlooked if not specifically searched for. We report 2 patients with nonNF1 RASopathies and anemic nevi.