Abstract: TH-PO466
Not All Light-Chain Restricted Pattern Is Light Chain Disease
Session Information
- Glomerular Diseases: Podocytopathies and Nephrotic Syndromes
November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1302 Glomerular Diseases: Immunology and Inflammation
Authors
- Daneshmand, Arvin, Georgetown University School of Medicine, Washington, District of Columbia, United States
- Kwon, Donghyang, MedStar Georgetown University Hospital, Washington, District of Columbia, United States
- Burka, Steven A., MedStar Georgetown University Hospital, Washington, District of Columbia, United States
- Pourafshar, Negiin, MedStar Georgetown University Hospital, Washington, District of Columbia, United States
Introduction
Light Chain Deposition Disease (LCDD) is a disease characterized by widespread tissue deposition of monoclonal Ig light chains (LC), often in association with immunoproliferative disorders.1 The clinical course of LCDD most often involves the kidney, as this is the primary site of LC uptake and degradation, and results in renal insufficiency. Microscopy most often reveals nodular sclerosing glomerulopathy or tubular basement membrane thickening, particularly with κ-LCs .2 Rarely, renal involvement may take the form of subepithelial deposits otherwise characteristic of membranous nephropathy (MN).3, 4 Here we highlight a case of kappa-predominant MN with no significant immunoglobulin deposition in a patient with monoclonal gammopathy.
Case Description
Our patient is a 66y/o female who presented with severe lower extremity edema and hypertension (SBP 200’s), found to have nephrotic syndrome with UPC 10.8, Cr 0.78. On further evaluation, labs revealed a small M spike of 0.12, gamma globulin 0.64, and alpha-2-globulin 1.26 on SPEP. Subsequent abdominal fat pad aspiration and colonoscopy with rectal biopsy were negative for amyloidosis. A bone marrow biopsy, FISH study, and flow cytometric analysis were all negative for hematologic malignancy. Left kidney biopsy in 05/2021 was notable for MN with granular kappa-predominant staining with no Ig deposition and mild chronic tubulointerstitial disease. Negative Congo Red stain excluded amyloidosis. She was determined to have monoclonal gammopathy of renal significance (MGRS) and was initiated on Velcade/dexamethasone. Initial serum Kappa free light chain level was 44.2, with subsequent improvement to 27.3 and reductions in proteinuria and edema.
Discussion
This patient found benefit to chemotherapy for MN secondary to MGRS. In summary, MGRS may cause nephrotic syndrome with only light chain subepithelial deposition in the absence of other tubular or glomerular toxicities.
Kappa Stain