Pseudo-Nonsecretory Multiple Myeloma with Light Chain Deposition Disease

Abstract

A diagnosis of nonsecretory myeloma was established in two patients with anemia and proteinuria on the basis of the suppression of polyclonal immunoglobulins and the increase of plasma cells in the bone marrow. No paraprotein was detected in the serum or concentrated urine of these patients. However, a plaque-forming assay of bone marrow cells showed the secretion of monoclonal immunoglobulin by the myeloma cells. Moreover, renal biopsies from both patients indicated the deposition of monoclonal light chains in the glomerular mesangium and basement membrane, as well as in the tubular basement membrane, a pattern consistent with light-chain deposition disease. These observations suggested that the secreted paraprotein disappeared rapidly as a result of enhanced catabolism or deposition in organs such as the kidney, producing severe proteinuria and chronic renal failure. The plaque-forming assay is a useful technique for the demonstration of this type of nonsecretory myeloma, pseudo-nonsecretory myeloma.

Acute Renal Failure due to Cast Nephropathy in Nonsecretory Myeloma: A Case Report and Review of the Literature

“…Serum and/or urine electrophoresis showed no M spike in 1 out of 9 cases [10]. This and other reports have documented light chain deposition disease [11], amyloidosis [12] and nodular glomerulosclerosis [13,14] in NSMM, raising the suspicion that abnormal proteins were secreted at some time during the course of gammopathy.…”

“…Another cause of negative electrophoresis could be intermittent immunoglobulin excretion, possibly due to variations in tumor mass. These cases have been referred to as ''pseudo-NSMM'' [5]. Our case showed k-chain deposition, suggesting tubular damage due to paraprotein secretion and fits in this category.…”

“…True nonsecretory cases exhibit either defective secretion due to decreased permeability of the cell membrane to immunoglobulin or abnormal transport of immunoglobulins to the cell membrane [3]. Cytoplasmic immunoglobulins can be demonstrated by immunoperoxidase technique in these cases [5]. In contrast, the immunoglobulin assembly within the plasma cells is defective in the nonproducer MM.…”

Systemic Mastocytosis Accompanied by a Non-Secretory Plasma Cell Dyscrasia and Nephrotic Syndrome-Level Proteinuria in a 76-Year-Old Patient

“…More importantly, systemic amyloidosis could be a cause of renal failure with nephrotic syndrome in this patient. As some case reports have previously shown, AL amyloidosis or renal failure secondary to a plasma cell neoplasm cannot be excluded even with a non-secretory myeloma [11,12,13]. As commented on by the authors of a relevant report [11], the secreted paraprotein could be rapidly cleared from the serum because of enhanced catabolism or deposition in organs such as the kidney, producing severe proteinuria and renal failure.…”

“…As some case reports have previously shown, AL amyloidosis or renal failure secondary to a plasma cell neoplasm cannot be excluded even with a non-secretory myeloma [11,12,13]. As commented on by the authors of a relevant report [11], the secreted paraprotein could be rapidly cleared from the serum because of enhanced catabolism or deposition in organs such as the kidney, producing severe proteinuria and renal failure. In a small study regarding the usefulness of serum free light chain assay in the diagnosis of primary systemic AL amyloidosis, the assay was positive in 97% of cases, excluding a small number of patients, whereas in a larger study, the serum free light chain ratio was abnormal in only 90% of patients [13,14].…”