Epidermal nevus syndromes: New insights into whorls and swirls

Abstract

Knowledge of the molecular underpinnings of many epidermal nevi and epidermal nevus syndrome has expanded rapidly in recent years. In this review and update on epidermal nevus syndrome, we will cover recent genetic discoveries involving epidermal nevi, including nevus sebaceus, keratinocytic epidermal nevus, nevus comedonicus, congenital hemidysplasia with ichthyosiform nevus and limb defects syndrome, phakomatosis pigmentokeratotica, Becker's nevus, porokeratotic adnexal ostial nevus, inflammatory linear verrucous epidermal nevi, and cutaneous-skeletal hypophosphatemia syndrome. We will discuss how newly defined mutations relate to the biology reflected in the cutaneous patterns seen in these mosaic disorders and how new molecular data has informed our understanding of these diseases and shaped management decisions. We will discuss the more well-delineated EN and ENS, including keratinocytic EN, nevus sebaceus, nevus comedonicus (NC), congenital hemidysplasia with ichthyosiform nevus and limb defects (CHILD) syndrome, phakomatosis pigmentokeratotica, Becker's nevus, porokeratotic adnexal ostial nevus (PAON), inflammatory linear verrucous EN (ILVEN), and the newly described cutaneous-skeletal hypophosphatemia syndrome (CSHS). We will examine advances in the genetics of these disorders and highlight promising work in the translation to management for our patients. We will also briefly discuss less well-defined EN and ENS associated with overgrowth syndromes.

Further delineation of the phenotypic spectrum of nevus comedonicus syndrome to include congenital pulmonary airway malformation of the lung and aneurysm

“…Epidermal nevi are benign areas of skin overgrowth involving the epidermis that may be present at birth or develop later in childhood and usually follow lines of Blaschko. These may be syndromic and occur with brain, eye, and skeletal manifestations (Asch & Sugarman, ). Nevus comedonicus syndrome is a rare variant of epidermal nevus that may begin as a linear shiny patch, sometimes noted at birth, and develops into plaques of dilated follicular openings filled with keratin plugs early in life, usually before the age of 10 years old (Tchernev et al, ).…”

“…Epidermal nevi are benign areas of skin overgrowth involving the epidermis that may be present at birth or develop later in childhood and usually follow lines of Blaschko. These may be syndromic and occur with brain, eye, and skeletal manifestations (Asch & Sugarman, 2018).…”

Keratinocytic Epidermal Nevus with Nevus Spilus and Underlying Hemihypertrophy

“…1,2 Presence of keratinocytic nevus and nevus spilus among with other abnormalities has been reported in some epidermal nevus syndromes. [1][2][3] Here a case of 5-year-old girl with keratinocytic epidermal nevus, nevus spilus and hemi-hypertrohpy which is not consistent with any of the reported ENSs, showing a rare coexistence, is presented.…”

“…ENSs are defined as the presence of an EN with associated involvement of other organ systems. 3 In recent years, data on different ENSs has expanded, and in some of these phenotypes the underlying molecular defects, clinical features and genetic patterns has been elucidated. 4 All ENSs are reported to reflect mosaicism.…”

A 3‐month‐old with papules and plaques in a blaschkoid distribution

“…Inflammatory linear verrucous epidermal nevus presents on the lower body as an intensely pruritic, unilateral array of linear erythematous and hyperkeratotic plaques that mimics psoriasis and is caused by a somatic mosaicism and presents within the first 5 years of life …”