Focal segmental glomerulosclerosis after membranous glomerulonephritis in remission: temporal diversity of glomerulopathy after bone marrow transplantation.
Heavy proteinuria after bone marrow transplantation (BMT) is rare. Pathology shows membranous glomerulonephritis (MGN) in most cases. After BMT, focal segmental glomerulosclerosis (FSGS) after resolution of MGN has not been reported. We describe a 13-year-old boy who had matched unrelated donor allogeneic BMT for relapsed acute lymphoblastic leukemia, complicated by chronic graft-versus-host disease. Nephrotic syndrome developed 1 year after BMT and renal biopsy revealed MGN. Immunosuppressive therapy achieved good clinical remission, and treatment was stopped after 15 months. He developed significant proteinuria 55 months later. The second renal biopsy showed FSGS without changes of MGN. This distinctive disease evolution gives inspiring implications. Complete morphological resolution of graft-versus-host disease-associated MGN, achieved in our case, has not been previously documented. Recurrent significant proteinuria after BMT is not necessarily due to previous renal lesion, and a repeat renal biopsy is indicated. The pathogenesis of MGN and FSGS are different, and different mechanisms of glomerular injury can interplay in a single patient after BMT. This case helps to expand our knowledge of the temporal morphological spectrum of renal lesions associated with BMT.