Clin Rheumatol DOI 10.1007/s10067-006-0238-x CASE REPORT Ömer Nuri Pamuk . Gülsüm Emel Pamuk . Ufuk Usta . Necati Çakir Hemophagocytic syndrome in one patient with adult-onset Still’s disease Presentation with febrile neutropenia Received: 7 September 2005 / Accepted: 9 September 2005 / Published online: 21 March 2006 # Clinical Rheumatology 2006 Abstract 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 anal- ysis 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. Keywords Adult-onset Still’ s disease . Febrile neutropenia . Hemophagocytosis . Macrophage activation syndrome Introduction Macrophage activation syndrome (MAS) is an intriguing, life-threatening complication of systemic-onset juvenile rheumatoid arthritis (JRA) [1–3]. Intensive activation and proliferation of T cells and macrophages cause MAS [2, 3]. This activation leads to a prominent systemic inflammatory response [2]. The pathognomonic feature of MAS is seen on bone marrow aspirates; many well-differentiated mac- rophages phagocytize hematopoietic cells [2]. Although MAS has been defined in systemic JRA, it has been reported in only a few cases of adult-onset Still’ s disease (AOSD) patients [4–9]. The development of cytopenias is an important feature of the disease; however, presentation with febrile neutropenia has not been reported in literature until now. Here, we present one patient with AOSD who later presented with febrile neutropenia, was diagnosed with MAS, and treated with high-dose steroids. Case report A 50-year-old female patient was referred to our rheuma- tology department with the complaints of diffuse myalgia, fever, skin rash, and pruritus. The patient admitted to having a sore throat for the last 3 weeks and said that she developed fever the night before, which was accompanied by a skin rash. She denied having photosensitivity, oral ulcers, Raynaud phenomenon, and sicca symptoms. Physical examination revealed polyarthralgia and 3 cm of spleno- megaly. Laboratory data were as follows: hemoglobin, 10.8 g/dl; leukocytes, 14,000 per cubic millimeter (with 86% neutrophils); platelets, 229,000 per cubic millimeter; erythrocyte sedimentation rate (ESR), 97 mm/h; C-reactive protein (CRP), 16 mg/dl (N 0–0.5); creatinine, 0.7 mg/dl; alanine transaminase (ALT), 75 U/l; albumin, 3.2 g/dl; Ö. N. Pamuk . N. Çakir Department of Rheumatology, Trakya University Medical Faculty, Edirne, Turkey e-mail: omernpamuk@yahoo.com G. E. Pamuk Department of Hematology, Trakya University Medical Faculty, Edirne, Turkey U. Usta Department of Pathology, Trakya University Medical Faculty, Edirne, Turkey N. Çakir (*) Altunizade, Okul Sokak, Erzurum Sitesi, No: 19/5, Üsküdar, 81190 Istanbul, Turkey e-mail: necaticakir@hotmail.com Tel.: +90-284-2350001 26: (2007) 797–800