Dermal melanocytosis: A clinical spectrum

Abstract

While most dermal melanocytoses are congenital or have an onset in early childhood, there is a group which is clearly acquired, with an onset in adult life. While the Mongolian spot typically disappears in childhood, other dermal melanocytoses persist for life. A brief review of the clinical spectrum of the dermal melanocytoses is undertaken and three illustrative cases are described: a case of congenital naevus of Ota, a case of acquired bilateral naevus of Ota-like macules, and an unusual case of a congenital dermal melanocytotic lesion on the left had which began to spread in adulthood. The possibilities regarding the pathogenesis of this intriguing group of disorders are considered.

An Unusual Case of Congenital Dermal Melanocytosis

“…It is believed that during embryogenesis, dermal melanocytes migrate from the neural crest to their designated site at the epidermal-dermal junction. Dermal melanocytosis occurs when the melanocytes fail to properly reach that designated site 8 .…”

Congenital Bilateral Dermal Melanocytosis with a Dermatomal Pattern

“…Unusual cases of DM are reported in the literature [2, 3, 4, 5]. They are either congenital or acquired, limited or spread over the body.…”

Melanotic Schwannoma Arising in Association With Nevus of Ota: 2 Cases Suggesting a Shared Mechanism

“…[25][26][27] Also known as oculodermal melanosis, it is thought to derive from incomplete migration of melanocytes from the neural crest to the epidermis during embryogenesis, resulting in dermal nesting and melanin production. 28,29 Nevus of Ota is most common in people of Asian descent, with the highest reported incidence of 0.2%-1.0% in Japanese patients. 30 A 3:1 female predominance suggests a possible hormonal component but may also reflect more frequent presentation due to cosmetic concerns.…”