Renal failure in a patient with two renal diseases: renal amyloidosis and rapidly progressive glomerulonephritis

Atypical case of AL amyloidosis with urinary erythrocyte casts

We present the case of a 73-year-old man who developed an acute, severe febrile illness with multiorgan dysfunction, featuring renal failure, nephrotic-range proteinuria, microhematuria, and a skin rash. Numerous erythrocyte casts were found on urine microscopy. Typically, the finding of urinary erythrocyte casts indicates the presence of an underlying glomerular inflammatory disease. However, on renal biopsy, only amyloid light-chain (AL) amyloidosis and tubular injury were the predominant findings with no signs of glomerular or vascular inflammation. Photomicrographs of urinary sediment as well as renal biopsy histopathology of the presented case are shown. The unusual combination of findings, is then discussed in light of the existing literature on renal amyloidosis as well as erythrocyte casts in conditions other than glomerulonephritis.

Monoclonal gammopathy-associated pauci-immune extracapillary-proliferative glomerulonephritis successfully treated with bortezomib

Extracapillary-proliferative glomerulonephritis is a rare complication of multiple myeloma. Partial remission of kidney involvement with cyclophosphamide therapy has previously been described. We report the case of a 60-year-old male patient diagnosed with rapidly progressive glomerulonephritis associated with IgG kappa monoclonal gammopathy. His kidney biopsy revealed pauci-immune extracapillary-proliferative glomerulonephritis without cryoglobulinaemia. Treatment with the proteasome inhibitor bortezomib induced rapid clinical and histological remission of his kidney disease. The patient's renal function remained stable on bortezomib maintenance therapy. Our findings suggest that bortezomib is a promising therapeutic approach to ameliorate severe kidney damage in monoclonal gammopathy- and myeloma-associated pauci-immune extracapillary-proliferative glomerulonephritis.