Successful treatment of nephrotic syndrome induced by lambda light chain deposition disease using lenalidomide: A case report and review of the literature

Background: Light chain deposition disease (LCDD) is a monoclonal immunoglobulin deposition disease (MIDD) that is characterized by the deposition of monoclonal light chains in multiple organs, including the kidney. It is a rare disorder caused by an underlying monoclonal plasma cell dyscrasia. LCDD with renal involvement causes proteinuria, which sometimes can lead to nephrotic syndrome. The monoclonal light chains are mostly in the kappa form. Treatment of LCDD is the same as that for multiple myeloma (MM); however, some conventional anticancer drugs show substantial toxicity and therefore cannot be administered to older patients or those with renal impairment. Case presentation: An 80-year-old woman was referred to our department with severe nephrotic syndrome (13.6 g/gCr) and anemia. A renal biopsy showed mesangial proliferation and mesangial matrix expansion, and immunohistochemistry showed positive staining for lambda chains along the glomerular basement membrane, but was negative for lambda chains or amyloid deposition. A bone marrow biopsy revealed 64% plasma cells. Immunoglobulin G (IgG)-lambda type M protein was detected, and the levels of free lambda chain was significantly increased. We concluded that her nephrotic syndrome was caused by LCDD, which resulted from IgG-lambda MM. The induction of a BCD (bortezomib, cyclophosphamide, and dexamethasone) treatment regimen did not lead to a hematological response or decrease in proteinuria. The administration of combination therapy of lenalidomide and prednisolone led to the successful reduction of proteinuria and hematuria. Conclusions: We presented a very rare case report describing the successful treatment of LCDD (lambda chain)-induced nephrotic syndrome with lenalidomide.