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Abstract: TH-PO438

Collagenofibrotic Glomerulopathy in a Patient With Waldenstrom Macroglobulinemia

Session Information

Category: Glomerular Diseases

  • 1301 Glomerular Diseases: Fibrosis and Extracellular Matrix

Authors

  • Gunasekaran, Deepthi, Yale University, New Haven, Connecticut, United States
  • Shirali, Anushree C., Yale University, New Haven, Connecticut, United States
Introduction

Collagenofibrotic glomerulopathy(CG) is a rare disease characterized by type III collagen deposition in the glomerular mesangial matrix and subendothelial space. It is unclear if this is a primary kidney disease or a systemic process. We report a unique case of CG in the setting of long-standing diabetes mellitus(DM) and malignancy.

Case Description

An 84-year-old female was referred to Nephrology for AKI. Her medical history was significant for CKD III, Waldenstrom macroglobulinemia(WM), lymphoplasmacytic lymphoma in remission after rituximab/bendamustine therapy, and DM with retinopathy, requiring insulin. She had no family history of kidney disease and an unremarkable physical exam. Labs were significant for creatinine of 1.9 mg/dl from a baseline of 1.3 mg/dl. UPCR was 0.33 mg/mg of creatinine and UACR was 95.3 mg/g of creatinine. Kappa-lambda light chain(LC) ratio was elevated at 4.98. Serum and urine immunofixation revealed IgM kappa monoclonal components. Kidney biopsy showed glomeruli with mesangial expansion and matrix deposition(weakly PAS positive, congo red negative) and diffuse tubular injury. Immunohistochemical stain for collagen type III showed 1+ mesangial staining. Electron microscopy showed mesangial deposits of collagen fibrils with periodicity. Her creatinine improved to baseline over the next 6 months without further therapy.

Discussion

Prior CG cases described patients ranging from 2-66 years, typically presenting with nephrotic proteinuria. While some cases have occurred de novo, others have shown association with lymphoma and DM. Our case is unique with advanced age and sub-nephrotic proteinuria. Although she had increasing kappa LCs and DM, there were no overt signs of WM, such as amyloid, or of DM on biopsy. This case raises the potential of CG as another manifestation of kidney involvement in WM.