Atypical Histiocyte-Rich Sweet’s Syndrome

Figure 2

Biopsy findings. (a) Histological section showing fairly prominent papillary dermal edema and a somewhat dense dermal infiltrate comprised of mixed inflammatory cells (hematoxylin-eosin, original magnification: ×40). (b) Many large histiocytic cells are present as well as lymphocytes and scattered neutrophils (hematoxylin-eosin, original magnification: ×400). Leukocytoclastic debris is noted, but evidence of vasculitis is lacking. (c) Myeloperoxidase immunohistochemical stain reveals scattered neutrophils but is negative in the histiocytic cells (original magnification: ×200). (d) Histiocytic cells are confirmed to be histiocytes and not mononuclear myelocytes (CD163 immunohistochemical stain, original magnification: ×100). (e) Background T lymphocytes (CD3 immunohistochemical stain, original magnification: ×100).

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