Bone marrow findings in patients with adult Still's disease

Objective: Peripheral neutrophilia is one of characteristic laboratory findings in patients with adult Still's disease (ASD). We performed this study to identify the bone marrow findings in patients ASD. Methods: We examined 12 bone marrow biopsy specimens from patients with ASD. Results: The most frequent finding was granulocyte hyperplasia (12/12, 100%) and hypercellularity was observed in 75.0% (8/12) of patients. Plasmacytosis was present in 8.3% (1/12) of specimens. Histiocytosis and reactive hemophagocytosis were found in 25.0% (4/12) and in 16.7% (2/12) respectively. Conclusion: Our results show that bone marrow granulocyte hyperplasia is the main possible mechanism for peripheral neutrophilia and that histiocytic activation is a not infrequent bone marrow findings in patients with ASD.