Background: Rosai-Dorfman disease is a non-Langerhans cell histiocytosis that recently has been treated successfully with imatinib mesylate in a patient with a systemic variant of the disease. Observations: We describe a 69-year-old man with cutaneous Rosai-Dorfman disease manifesting as progressive, deeply infiltrated skin lesions. Histopathologic examination of the lesions demonstrated dense dermal infiltrate positive for CD68, stabilin-1, and S-100, but not for CD1a. The histiocytes were positive for plateletderived growth factor receptor ␣, the target molecule for imatinib. During the 5-year course of the disease, multiple therapeutic approaches (tuberculostatic drugs, topical and systemic glucocorticoids, thalidomide, isotreti