Resolution of mesangial light chain deposits 3 years after high-dose melphalan with autologous peripheral blood stem cell transplantation.

A 52-year-old woman was admitted to our hospital for treatment of nephrotic syndrome. Funduscopic findings showed fundal hemorrhage and soft exudates, and serologic analysis showed a monoclonal serum component that was identified as Bence Jones protein-k type. A bone marrow biopsy showed diffuse proliferation of atypical plasma cells, while a renal biopsy showed diffuse and nodular mesangial proliferation. Immunohistochemical staining confirmed the presence of k chains along the glomerular basement membrane and in mesangial areas. The patient was diagnosed as multiple myeloma (Bence Jones k type) with light chain deposition disease (LCDD). After high-dose melphalan and autologous peripheral blood stem cell transplantation (PBSCT), the multiple myeloma and nephrotic syndrome were in complete remission; her renal function was improved, but a renal biopsy performed 6 months after PBSCT showed the persistence of diffuse and nodular lesions. By contrast, a renal biopsy performed 3 years later showed complete resolution of the diffuse and nodular mesangial proliferation.