Psoriasiform graft‐versus‐host disease distributed along Blaschko's lines

Abstract

This case presents an unusual manifestation of cutaneous chronic graft-vs-host disease (cGVHD) mimicking psoriasis along Blaschko's lines. Such a presentation may pose a particular challenge to providers as it is quite rarely reported, and, therefore, it is possibly misdiagnosed. cGVHD may mimic psoriasis and should be considered in any patient previously transplanted even with a previous history of psoriasis. A Blaschkoid pattern of cGVHD is unusual and may be the manifestation of an immune reaction unveiling a previously masked mosaicism.

Scaly plaques in a post‐hematopoeitic stem cell transplant patient

“…It can also rarely occur after transfusion of blood products, solid organ transplant, and autologous HSCT 5 . GVHD is a major cause of morbidity and mortality in patients receiving HSCT, and the skin is the most commonly affected organ 2,4,6–8 …”

“…The exact mechanism for the coexistence of these entities is unknown, however it is believed that the interaction of donor lymphocytes and recipient keratinocytes during GVHD induces keratinocyte hyperproliferation 1,2,4,8 . Both are T‐cell mediated processes that show a Th1 cytokine secretion profile with secretion of IFN Ɣ and IL‐17 by Th17 cells 2,4,6–8 . Lesional skin in GVHD displays elevated HLA‐DR antigen expression in epidermal keratinocytes as well as a decrease in Langerhans cells, the same as in psoriasis 2,7 …”

“…5 GVHD is a major cause of morbidity and mortality in patients receiving HSCT, and the skin is the most commonly affected organ. 2,4,[6][7][8] GVHD is currently classified according to its clinical and histopathological features and is divided into subcategories: classic, persistent, recurrent, or late onset acute GVHD; classic chronic; and overlap syndrome. 5 The typical cutaneous manifestations of acute GVHD are erythematous morbilliform eruptions, follicular erythema, or toxic epidermal necrolysis-like eruptions.…”

Blaschkoid Acute Graft-vs-Host Disease

“…A blaschkoid pattern is characteristic of epidermal nevi and some genodermatoses, but it has also been noted in several acquired inflammatory dermatoses including vitiligo, lichen planus, psoriasis, morphea, lichen sclerosus, lupus erythematosus, and drug eruptions . Blaschkoid chronic GVHD has been reported infrequently, manifesting as lichenoid and rarely as a psoriasiform eruption . Many of these patients had prior acute GVHD, but this was not reported to be in a blaschkoid pattern.…”

“…A postzygotic mutation in a clone of migrating epidermal cells would manifest itself along the lines of Blaschko. It is hypothesized that in some people, this postzygotic mutation is clinically silent until donor lymphocytes from a bone-marrow allograft attack the mutated cells resulting in a blaschkoid pattern of GVHD . The development of linear GVHD has also been ascribed to an isotopic phenomenon at sites of previous herpes zoster eruption .…”