A case of primary (AL) amyloidosis with predominantly vascular amyloid deposition in the kidney.

We report a 70-year-old man with primary (AL) amyloidosis with predominantly vascular deposition of amyloid diagnosed by renal biopsy, who was successfully treated using two chemotherapy regimens. There was rapid elevation of the serum creatinine level without remarkable proteinuria or hematuria. Renal histological examination showed some thickened arterial walls with amyloid fibril accumulation, and only a small amount of amyloid deposition in the glomeruli. Immunohistochemical examination was positive for anti-kappa staining. Serum immunoelectrophoresis and immunofixation testing did not show monoclonal proteins, and urine immunoelectrophoresis did not show Bence-Jones proteins. Serum free light chain (FLC) analysis showed that the serum FLC level and FLC kappa/lambda ratio were abnormally high for his renal function. He received two courses of VAD (vincristine, doxorubicin, and dexamethasone), followed by BD (bortezomib and dexamethasone), resulting in a hematologic partial response. Renal amyloidosis with vascular-limited amyloid deposition has few urinary findings. Early diagnosis of this condition is challenging, because kidney biopsies are not usually performed in patients without significant urinary findings. We suggest several currently available methods of achieving earlier detection of this condition.