Hemophagocytic syndrome in one patient with adult-onset Still's disease. Presentation with febrile neutropenia.

Macrophage activation syndrome (MAS) is an important complication seen in systemic for juvenile rheumatoid arthritis; until now, it has been reported in only a few cases of adult-onset Still's disease (AOSD). Here, we shall present a 50-year-old female patient who was using steroids and antimalarial drugs for AOSD, and who developed MAS during follow-up. The patient presented with febrile neutropenia, and the neutropenic period lasted for 15 days. The examination of bone marrow aspiration smears demonstrated increased macrophages and findings of hemophagocytosis. Flow cytometric analysis of peripheral blood showed decreased natural killer cells. The patient developed neurologic findings during this period, and during the recovery of neutropenia, she had icterus and liver function test abnormalities. The patient was given granulocyte colony-stimulating factor during neutropenic period, and her neutropenia improved after the administration of high-dose steroids. Our patient was the first AOSD patient who presented with febrile neutropenia during the course of her disease and who was diagnosed to have MAS.