Drug-associated histiocytoid Sweet's syndrome: a true neutrophilic maturation arrest variant.

Histiocytoid Sweet's syndrome is a recently described entity which has clinical features identical to typical Sweet's syndrome but is distinguished by a dermal cellular infiltrate composed not of mature neutrophils but of immature granulocytes. Herein, we report a case of bone marrow granulocytic maturation arrest and a histological histiocytoid Sweet's-like reaction pattern following trimethoprim-sulfamethoxazole therapy.