Typically atypical: histiocytoid Sweet syndrome, associated with malignancy.

Sweet syndrome (acute febrile neutrophilic dermatosis) is characterized by a dramatic onset of high fever, neutrophilia and typical skin lesions. About 20 % of patients have an associated malignancy, most commonly hematologic diseases. Chronic and paucisymptomatic manifestations of Sweet syndrome may be misdiagnosed or misinterpreted as harmless, resulting in delayed diagnosis. "Atypical" manifestations are especially suspicious for associated malignancies. This is demonstrated by a 39-year old patient with chronic and afebrile disease who was referred to our clinic only after symptoms had persisted for several months. By that point, an underlying nodular lymphocyte predominant Hodgkin's lymphoma had already reached an advanced stage. Skin biopsies revealed dermal infiltrates of histiocytoid cells of myelogenous origin, supporting a diagnosis of histiocytoid Sweet syndrome. Specific cutaneous infiltrates associated with myelogenous leukemia were ruled out.