Simultaneous tubular and glomerular involvement with cryoglobulinemia vasculitis in multiple myeloma.

Renal manifestations in myeloma are varied. Tubulopathic light chains cause cast nephropathy or proximal tubulopathy, usually associated with tubulointerstitial nephritis. Glomerular involvement includes amyloidosis and monoclonal immunoglobulin deposition diseases. We report a case of multiple myeloma with systemic manifestation of Type-1 cryoglobulinemic vasculitis (skin rash and polyarthritis) and unusual renal manifestation with both tubular and glomerular involvement on renal biopsy along with features of cryoglobulinemic renal vasculitis. Renal biopsy showed light chain cast nephropathy and glomerular involvement. Glomeruli displayed membranoproliferative pattern with monoclonal immunoglobulin deposition disease and features of cryoglobuminemia. Immunoflourescence showed Kappa restriction in the tubular casts and glomerular deposits. Serum light chain assay and immunoelectrophoresis revealed IgG Kappa light chain restriction. The exact mechanism of the varied renal manifestations of multiple myeloma in different patients is not known.