Light chain nephropathy with remarkable accumulation of multinucleated giant cells in the kidney

A case of light chain deposition disease with multinucleated giant cell accumulation in the kidney is described. A 54-year-old man was admitted to out hospital due to moderate renal failure. Complicated with eosinophilic pneumonia two months after admission, his renal function abruptly deteriorated and hemodialysis was started. Three-day methylprednisolone pulse therapy, however, partially recovered his renal function and hemodialysis was discontinued. His renal biopsy specimen revealed kappa light chain deposition disease with nodular mesangial expansion and subendothelial electron dense deposits. The most characteristic finding in this patient was accumulation of foreign body type multinucleated giant cells around atrophic tubules, small arteries and obsolescent glomeruli, probably associated with light chain deposition. No increase in kappa light chain was detected in his serum or concentrated urine. Such disseminated giant cell reaction, other than intra-luminal infiltration in the tubules, has not been reported in the literature and might be related to the physicochemical or structural properties of the deposited protein.