Trauma as Triggering Factor for Development of Melanocytic Nevi

Abstract

The mechanisms for the development of acquired melanocytic nevi remain mostly unclear. Here we report a case of eruptive nevi that developed after localized superficial trauma, and review the currently known cellular and triggering factors for acquired melanocytic nevi. A 66-year-old woman presented a linear arrangement of pigmented macules on her left calf that developed after a bloodless skin erosion on the same spot, resulting from friction with the lining of a ski boot. Dermatopathology identified multiple junctional proliferations of single or small nest-forming melanocytes with bridging, pigment incontinence and moderate cellular atypia. The number of a person’s nevi correlates with age, race and genetics, but blistering diseases, scarring processes, light exposure and immunosuppression can contribute to nevocellular growth as well. Damaged keratinocytes and inflammatory cells can release growth factors inducing nevus cell proliferation, and immunosuppression could end cellular surveillance keeping preexisting nevus cell nests in check. We conclude that in predisposed patients, the trigger for eruptive nevi can be reduced to a simple localized minor trauma.

Agminated Spitzoid Naevi after Remission of Langerhans Cell Histiocytosis: First Italian Case and Literature Review

“…Pathogenesis of agminated naevi in patients with LCH history is not yet entirely clear. Eruptive naevi can be idiopathic or linked to trauma, burns, cutaneous mastocytosis, and primary adrenocortical insufficiency (6)(7)(8). In the literature, the development of multiple melanocytic naevi is often associated with an underlying trigger (6).…”

“…Eruptive naevi can be idiopathic or linked to trauma, burns, cutaneous mastocytosis, and primary adrenocortical insufficiency (6)(7)(8). In the literature, the development of multiple melanocytic naevi is often associated with an underlying trigger (6). It has been commonly associated to severe blistering skin diseases, such as naevi in epidermolysis bullosa, or to immunosuppressive conditions (7)(8)(9)(10).…”

“…Inflammatory cells can release growth factors inducing naevogenesis, and immunosuppression could stop the cellular surveillance keeping preexisting naevus cell nests in check. Thus, in predisposed patients, the specific trigger factor for the development of eruptive naevi could be frequent and localized friction (6). Considering the hypothesis of a common origin of epidermal melanocytes and Langerhans cells from epidermal cam-bial cells, we searched for the B-RAF mutation in both neoplastic Langerhans cells and naevocytic melanocytes (13).…”

Conjunctival Blue Naevus in an Anophthalmic Socket

“…There are several case reports that have documented the development of bona fide melanocytic naevi, including so-called “eruptive blue naevi” at sites of sunburn [21], previous trauma [22], and infection [23]. Mechanisms that have been proposed are the release of growth factors from keratinocytes and inflammatory cells triggering melanocyte proliferation [21,22,23]. To the best of the authors' knowledge, this is the first report of a conjunctival blue naevus occurring in an anophthalmic socket.…”

”Bathing Trunk” Eruption of Papules and Nodules in a Young Woman: A Quiz

“…Despite reported associations with sun-exposure, pregnancy, intravenous drug abuse, and post-operative stress, the pathogenesis of ESDN is largely unknown (2,5). More generally, factors that may predispose to eruptive melanocytic naevi include anti-neoplastic and immunosuppressant drugs, blistering diseases, immunodepression, hormonal changes, and systemic infections; naevogenesis would ensue owing to increased levels of growth stimuli, loss of control from the immune system, and/or genetic damage (2,6).…”