Desmoplastic Hypopigmented Hairless Nevus: A Variant with Progressive Depigmentation, Induration, and Overgrowth

Abstract

Large congenital melanocytic nevus rarely presents itself without hairs, with hardened skin and progressive depigmentation. We report a girl who presented with a large congenital melanocytic nevus in the left cheek. Over the years, the nevus became pruriginous, light brown, bumpy, and hard. Histology revealed nevus cells interspersed with dense fibrosclerotic collagen bundles. There are few reported cases of large congenital melanocytic nevus with this evolution, so-called desmoplastic hypopigmented hairless nevus.

Sclerotic Regressing Large Congenital Nevus

“…All published cases of sclerotic hypopigmented GCMNs were found in infancy and childhood; none have been described beginning in adults. None of these cases showed inflammatory regression . Sclerotic hypopigmented GCMNs have a firm to hard consistency and variable pigmentation, resembling morphea .…”

“…None of these cases showed inflammatory regression . Sclerotic hypopigmented GCMNs have a firm to hard consistency and variable pigmentation, resembling morphea . They are mainly located on the trunk, often involving the buttocks and perineum .…”

“…Metaplasia or differentiation of melanocytes into adaptive fibroblasts and tumor extracellular matrix interactions may lead to the induction of collagen synthesis . This reaction may start in utero and last as long as the immune system recognizes nevus antigens .…”

“…Fibrosis is progressive, and nevus cells are depleted, resulting in pigment loss. This process also involves hair follicles, resulting in alopecia or hypotrichosis . Another less frequent step in the evolution of this process is softening of induration, attributed to the subsequent decrease in the burden of nevus cells .…”

“Sky Full of Stars” Pattern: Dermoscopic Findings in a Desmoplastic Giant Congenital Melanocytic Nevus

“…Histology shows filamentous tissue invasion that involves a reduction in melanocytic cells. These cells remain arranged in cords and nests at the dermoepidermal junction, wrapped in thick collagen bands, which explains the hypopigmentation and sclerosis. There can also be follicular destruction due to sclerosis around the hair follicles .…”