QUIZ

WHAT IS YOUR DIAGNOSIS?

A 17-year-old girl presented with a 7-year history of progressive and coalescent purpuric, pigmented, non-pruritic macules (Fig. 1). The first skin biopsy taken in 2007 showed hyperkeratotic epidermis, slightly dilated capillaries and mild lymphocytic infiltrates with granulomas in the papillary dermis (Fig. 2).

After a 16-month follow-up, a second skin biopsy revealed a dense, band-like lymphohistiocytic infiltrate, occupying the papillary and upper reticular dermis, composed of small, mildly atypical cells; single cells migrated into the epidermis (Figs. 3, 4). The lymphocytes were CD3+, CD4+, CD8+, with a CD4 : CD8 ratio of 2 : 1, and a 30% reduction of CD7 expression. Granulomatous reaction and hemosiderin deposits were also present (Fig. 5).

Due to apparent disease progression three months later, a third biopsy was taken; the histological picture was similar to the second biopsy, but the density of the lymphocytic infiltrate slightly decreased. TCR gene rearrangement analysis revealed an oligoclonal T-cell population.