Missed monoclonal disease manifesting in early post-renal transplant period

A 63-year-old diabetic gentleman with microvascular complications presented with advanced azotemia and anemia. He was stabilized with blood transfusion and hemodialysis. With the probable diagnosis of diabetic nephropathy-related end-stage renal disease, he underwent kidney transplantation. He had delayed graft function. Graft biopsy done on the 2nd postoperative day showed acute tubular necrosis. Graft biopsy repeated after 2 weeks for persistent graft dysfunction showed myeloma cast nephropathy (MCN) and light chain proximal tubulopathy. Work-up for multiple myeloma was positive. He was started on plasmapheresis and chemotherapy. However, he suffered sudden cardiac death during dialysis after 1 week. The presence of MCN in the early graft biopsy implies that it must have been the cause for his native kidney failure. Thus, renal failure in a diabetic should not always be presumed to be due to diabetic nephropathy, and kidney biopsy should be done in diabetics with atypical features.