Nephrotic Syndrome and Rapidly Progressive Renal Failure in a Patient with a Monoclonal Component: A Case Report

We present the case of a 53-year-old woman with nephrotic syndrome, progressive worsening of renal function, anemia, and detection of an IgG lambda monoclonal component. The clinical picture was characterized by nephrotic-range proteinuria, active urinary sediment, selective hypocomplementemia (reduced C3), splenomegaly, and multiple lymphadenopathies. Immunological and infectious investigations were negative. Serum and urine electrophoresis documented an IgG λ monoclonal component with a marked increase in free λ light chains. A kidney biopsy was performed to define the histopathological features and guide therapeutic management. This case highlights the importance of timely multidisciplinary evaluation in nephropathies associated with monoclonal gammopathy of renal significance (MGRS).