A boy with membranous nephropathy after allogeneic bone marrow transplantation

A 6-year-old boy developed bronchiolitis obliterans organizing pneumonia and nephrotic syndrome 5 months after allogeneic bone marrow transplantation from an unrelated donor for acute lymphoblastic leukemia. His renal biopsy showed membranous nephropathy. He was treated with prednisolone and cyclosporine A. Proteinuria disappeared 3 months after the onset of nephrotic syndrome. To our knowledge, this patient is the youngest case with nephrotic syndrome due to membranous nephropathy after hematopoietic stem cell transplantation.