First diagnosis of multiple myeloma in a kidney transplant recipient (a case report)

Background. Kidney graft failure due to recurrence of previously undiagnosed multiple myeloma (MM) is a rare event. This report presents a clinical case of kidney transplantation complicated by graft dysfunction one year after surgery caused by recurrence of undiagnosed MM. Clinical observation. A 75-year-old man with a history of arterial hypertension and diabetes mellitus was admitted to the dialysis unit with symptoms of uremia. He had not previously been followed by a nephrologist. Renal ultrasonography revealed diffuse parenchymal changes. Considering the two diseases, chronic kidney disease (CKD C5) secondary to hypertensive and diabetic nephropathy was diagnosed, and maintenance hemodialysis was initiated. After 11 months, the patient underwent deceased-donor kidney transplantation. One year post-transplantation, graft dysfunction developed, prompting a transplant kidney biopsy. Histopathological examination revealed changes characteristic of MM-associated kidney injury, including light-chain cast nephropathy (LCCN, κ type) combined with light-chain proximal tubulopathy (LCPT, κ type), focal segmental glomerulosclerosis, tubulointerstitial nephritis, and acute tubular necrosis. Further evaluation confirmed MM with Bence–Jones proteinuria, stage III B, and myeloma nephropathy of the renal allograft. The patient was transferred to the hematology department for chemotherapy, resulting in partial hematologic remission. However, renal graft function was not restored, and the patient remained on maintenance hemodialysis. Conclusion. MM-associated kidney injury is a rare clinical event. In routine clinical practice, thorough pre-transplant evaluation and accurate determination of the etiology of CKD are essential.