Desmoplastic hairless hypopigmented naevus: a variant of giant congenital melanocytic naevus

Abstract

Desmoplasia has been described in melanoma and Spitz naevus but not in giant congenital melanocytic naevus (GCMN). In melanoma desmoplasia is associated with a better survival. Four paediatric patients with hard, ligneous, progressively hypopigmented and alopecic GCMN were seen among 143 cases of GCMN at the Department of Dermatology of the National Institute of Paediatrics, Mexico City. Clinically, induration was progressive in three patients and regressive in one. Pigmentation was regressive in all. Histopathologically, all four patients showed intense dermal fibrosis, scarce naevus cells, and hypotrophic or absent hair follicles. Follow-up and serial biopsies in three patients documented the progressive nature of fibrosis and naevus cell depletion. No evidence of malignant transformation was found. Naevus cell depletion resulted in pigment loss and may have reduced the risk of malignant transformation. Although the cause of fibrosis is unknown, the possibility of an immune reaction to naevus cells is postulated.

Desmoplastic giant congenital nevus with progressive depigmentation

“…9 The key to the development of the fibroblastic reaction seems to be multidirectional differentiation of melanocytes into adaptive fibroblasts as well as tumor extracellular matrix interactions that lead to the induction of the collagen synthesis by the fibroblasts. 6,9,11 The explanation for the continuation of the sclerotic process in some patients is open to speculation. The elimination of the nevus cells could be responsible for the loss of the induration only in certain instances.…”

“…An autoimmune origin has been postulated for the pathogenesis of this variant of giant nevus. 6 The lack of hair may be the result of connective tissue proliferation suffocating hair follicles that became hypotrophic or absent.…”

“…5 Despite this, in exceptional cases, the involution process of the nevus is associated with changes in skin texture, especially with sclerosis and hair loss. [6][7][8][9] The most accepted mechanisms related to the depigmentation of melanocytic nevi are the destruction of melanocytes due to an autoimmune process and the diminished melanin-production capacity of nevus cells. 10 We report the case of a girl with an indurated, hairless, and intensely pruritic large congenital nevus, with a prominent desmoplasia histologically, which underwent a progressive depigmentation associated with loss of its hard consistency.…”

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

“…Desmoplastic giant congenital melanocytic nevus (DGCN) is an uncommon variant of congenital nevus that has only rarely been reported. It presents as a progressive induration and hypopigmentation that occasionally causes hair loss and even total or partial disappearance of the nevus . Other than cases that were removed surgically, the induration partially or completely disappeared in most reported cases but persisted in a minority , with excision performed in others, so the final outcome could not be known.…”

Congenital Melanocytic Nevi

“…Desmoplastic hairless hypopigmented nevus (DHHN) was fi rst described by Ruiz-Maldonado et al [ 44 ] as a hard, ligneous, progressively hypopigmented and alopecic GCMN. In such cases they noted progression of the induration in three cases and regression in the other patient.…”