Kidney Transplantation in a Patient with Smoldering Multiple Myeloma: A Case Report and Narrative Literature Review

Chronic kidney disease and end-stage kidney disease are frequently observed in patients with plasma cell dyscrasias, including monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, and multiple myeloma, although kidney failure is not always directly attributable to the hematologic disorder. Kidney transplantation represents the treatment of choice for end-stage kidney disease; however, the presence of an underlying plasma cell disorder poses significant clinical challenges and may limit access to transplantation. We report the case of a 73-year-old woman with end stage kidney disease and low-risk smoldering multiple myeloma who underwent a comprehensive pre-transplant evaluation, including a kidney biopsy that excluded myeloma-related nephropathy and supported a non–plasma cell–related etiology of kidney failure. The patient subsequently underwent deceased-donor dual kidney transplantation. Seventeen months after transplantation, she progressed from smoldering multiple myeloma to symptomatic multiple myeloma, requiring chemotherapy with a bortezomib-, thalidomide-, and dexamethasone-based regimen. Treatment resulted in a very good partial hematologic response according to International Myeloma Working Group criteria, accompanied by stable kidney graft function. This case suggests that kidney transplantation may be feasible in carefully selected patients with SMM following thorough pre-transplant evaluation. However, it also highlights substantial risks of post-transplant disease progression and malignancy, underscoring the need for rigorous risk stratification, multidisciplinary decision-making, and close post-transplant surveillance.