Abstract: PO1716
Idiopathic Fibrillary Glomerulonephritis: A Report of Two Cases
Session Information
- Glomerular Diseases: Fibrosis and Extracellular Matrix
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Report
- 1201 Glomerular Diseases: Fibrosis and Extracellular Matrix
Authors
- Sharma Priamvada, Gargi, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Kallapur, Aneesh S., Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, Tamil Nadu, India
- Lozano, Josue A., Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Jawa, Pankaj, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Jain, Koyal, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
Introduction
Fibrillary glomerulonephritis(FGN) is a rare glomerular disease characterized by the presence of fibrillar deposits in glomeruli and is associated with poor prognosis, often leading to end stage renal disease(ESRD). Previously considered to be idiopathic, new data suggests there is a secondary association in 30-50% of cases with underlying hepatitis C infection,malignancy,dysproteinemia and autoimmune disease. Immunohistochemical staining for DNA-J heat shock protein B9(DNAJB9) is emerging as a marker for rapid diagnosis of FGN.
Case Description
We report two patients with FGN who initially presented with monoclonal gammopathy(MG), but varied clinical courses. First patient, 60 year-old female presented with MG(IgG4 subclass), acanthocyturia and nephrotic syndrome. Renal biopsy showed PAS positive deposits in capillary loops and mesangium; Immunofluorescence microscopy showed IgG, C3, κ and λ light chains. Electron microscopy showed 20nm non-branching randomly arranged fibrils. Five years later, she is still in remission after treatment with bortezomib,cyclophosphamide and dexamethasone. Another 63 years old female presented with renal failure, positive pANCA and MG. Biopsy showed DNAJB9-positive sclerosing and proliferative FGN with 10% cellular crescents and severe interstitial fibrosis and tubular atrophy. She was treated with corticosteroids and rituximab for idiopathic FGN mimicking type III RPGN. However, she became dialysis dependent.
Discussion
FGN has broad presentation and course despite aggressive therapy. A study determined the strongest predictor of outcome to be initial serum creatinine. Other predictors were age,degree of glomerulosclerosis and proteinuria. Knowledge of pathogenesis along with renal pathology can help differentiate this from other fibril deposition diseases like amyloidosis and immunotactoid glomerulopathy. It is imperative to promptly identify FGN as it often progresses to ESRD and has limited data on optimal therapy.
Immunohistochemistry stain for DNAJB9. Glomerulus show diffuse extracellular smudgy staining. mag x200.