Renal-Limited Amyloid Light-Chain (Lambda) Amyloidosis Presenting as Monoclonal Gammopathy of Renal Significance: A Case Report

Monoclonal gammopathy of renal significance (MGRS) encompasses renal diseases caused by nephrotoxic monoclonal immunoglobulins produced by small B-cell or plasma cell clones that do not meet the criteria for overt hematologic malignancy. Renal amyloid light-chain (AL) amyloidosis is a recognized lesion within the MGRS spectrum. We report the case of a 66-year-old woman who presented with nephrotic syndrome and renal dysfunction associated with monoclonal lambda light chains. Renal biopsy confirmed AL (lambda) amyloidosis, while bone marrow examination and systemic evaluation revealed no evidence of multiple myeloma or systemic amyloid deposition. This case highlights that early recognition of MGRS-associated renal amyloidosis is essential, as delayed therapy may contribute to preventable morbidity and mortality.