Epidermal Nevus Syndromes

The term epidermal nevus syndrome (ENS) was originally used as an all-encompassing term used to describe epidermal nevi in association with other syndromic features. In more recent years, this term was expanded to include several more well-defined neurocutaneous syndromes and their association with an epidermal nevus. The genetic basis of many of these syndromes has been elucidated in recent years. However, much is still to be learned about the genotype-phenotype correlation. Common epidermal nevi include non-epidermolytic keratinocyte nevus, nevus sebaceus, nevus comedonicus, Becker’s nevus, and CHILD (congenital hemidysplasia with ichthyosiform nevus and limb defects) nevus. These are hamartomas of the skin, which are grouped as either organoid or keratinocytic. The syndromes included within this umbrella term are somewhat controversial. Therefore, the most frequently included syndromes will be discussed further. Schimmelpenning syndrome, phacomatosis pigmentokeratotica, nevus comedonicus syndrome, and Becker nevus syndrome are among the syndromes associated with organoid epidermal nevi. The syndromes associated with keratinocytic nevi include proteus syndrome and CHILD syndrome.