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JAMA Dermatology Clinicopathological Challenge
March 4, 2020

A Solitary Scaly Plaque on the Lower Extremity of a Young Girl

Author Affiliations
  • 1University of Louisville School of Medicine, Louisville, Kentucky
  • 2Department of Dermatology, The University of Utah, Salt Lake City
JAMA Dermatol. 2020;156(5):585-586. doi:10.1001/jamadermatol.2020.0059

A preschool-age girl presented for evaluation of an asymptomatic plaque on the right lower extremity that had been present for 1 year. Prior treatments included triamcinolone ointment and frankincense with no improvement. A potassium hydroxide preparation had negative results for fungal elements. Her medical history and family history were unremarkable. An examination found a 1-cm nummular plaque with centralized micaceous scale and a smooth erythematous border on the right lateral lower leg (Figure, A). A tangential-shave biopsy was performed to characterize the lesion. Histopathological testing revealed an epidermis featuring elongated rete ridges, keratinocyte enlargement, and a few Civatte bodies, with overlying parakeratotic crust and neutrophilic cell debris. Marked epidermotropism of atypical lymphocytes with irregular nuclear contours and halos, both singly and in small collections (Pautrier microabscesses) were also observed (Figure, B and C). Also, lymphocytes were present along the epidermal side of the dermoepidermal junction. Periodic acid–Schiff stained sections failed to show fungal or yeast elements. Immunohistochemical staining was markedly positive for CD3, CD5, and CD8 (Figure, D); CD4 reactivity was less robust and mainly restricted to dermal lymphocytes. Also, CD20 was present in 5% of dermal lymphocytes, and CD30 showed variable staining of 5% of lymphocytes.

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