Imatinib as a treatment option for systemic non-Langerhans cell histiocytoses.

BACKGROUND Systemic non-Langerhans cell histiocytoses are disorders characterized by the accumulation of histiocytes that do not meet the criteria for Langerhans cells in various organs. So far, no causative treatment is known. OBSERVATIONS Herein, we report the case of a 41-year-old man with Rosai-Dorfman disease, a form of systemic non-Langerhans cell histiocytoses, with histiocytic infiltrations in the skin, bone marrow, liver, and spleen. Histiocytes were positive for the imatinib target proteins platelet-derived growth factor receptor beta and KIT. The disease completely responded to treatment with 400 to 600 mg daily of imatinib for more than 7 months. CONCLUSION This case shows that imatinib is a powerful treatment option for patients with non-Langerhans cell histiocytoses.