Minimal change nephropathy in a 7-year-old boy with Rosai-Dorfman disease.

Rosai-Dorfman (R-D) disease is a benign lympho-histiocytosis of the lymphoid system. Immune derangement due to cytokine over-expression (tumor necrosis factor (TNF), interleukin (IL)-1b and IL-6) has been considered the cause of R-D disease. We present a 7-year-old boy with R-D disease who developed minimal change nephropathy (MCN) during the progression of R-D disease. The patient was resistant to oral prednisolone; and the remission of both R-D disease and MCN was achieved with oral cyclophosphamide (2 mg/kg, 12 weeks). MCN, the most common cause of nephrotic syndrome in childhood, is generally accepted to emerge by way of cytokine derangement. Correlation between R-D disease activity and the development and remission of nephrotic syndrome in our case suggested that nephrotic syndrome had been induced through some R-D disease-related immune mechanisms.