[Monoclonal gammopathies and kidney: a diagnostic challenge without any clues].

Diagnosis of monoclonal gammopathy of renal significance (MGRS) with histopathologic features of proliferative GN with monoclonal immunoglobulin deposits (PGNMID) is a challenge for clinicians because of the absence of laboratory findings suggestive of glomerular involvement in paraproteinemia. Renal biopsy remains the gold standard for diagnosis of PGNMID because it is a monoclonal gammopathy with kidney damage often "without a detectable serum/urine clone". Through this case report, we want to focus on the complexity both in the diagnostic process and in monitoring the renal-hematological response to therapy.