Abstract: TH-PO942
A Rare Case of Dual Glomerulopathy: Fibrillary Glomerulonephritis (FGN) and Membranous Nephropathy (MN) in a Patient with Chronic Inflammatory Demyelinating Polyneuropathy
Session Information
- Glomerular Trainee Case Reports
November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Report
- 1201 Glomerular Diseases: Fibrosis and Extracellular Matrix
Authors
- Shahzad, Sheikh Raza, Albany Medical Center, Albany, New York, United States
- Gosmanova, Elvira, Stratton VA Medical Center and Albany Medical College, Albany, New York, United States
- Foulke, Llewellyn A., Albany Medical Center, Albany, New York, United States
- Hongalgi, Krishnakumar D., Albany Medical Center, Albany, New York, United States
Introduction
FGN is a rare glomerular disease characterized by random fibrillary deposits. Usually idiopathic, it can be associated with malignancy, monoclonal gammopathy, or autoimmune disease. Its association with MN with CIDP is rare.
Case Description
A 68-year-old Burmese female presented with lower extremity edema and paraparesis of a 3-month duration. Her history was significant for latent tuberculosis, HTN and uncontrolled DM2 (last A1c of 14.5%). On exam, hypertension, renal anasarca and paraparesis were noted. Labs were significant for hypoalbuminemia (1.8) and nephrotic range proteinuria (6.8g/24hr). Serum Cr was at baseline (0.6). ANA (320), C3, C4, and Kappa/Lambda ratio (1.86) were mildly elevated. HIV, hepatitis panel, RPR, anti-dsDNA Abs, SPEP, UPEP, antiphospholipid Abs, cryoglobulins were negative. CT scan showed left renal vein thrombus. Electromyography showed mixed axonal polyneuropathy and she was diagnosed with CIDP. Renal biopsy revealed diffuse mild mesangial expansion, Congo red negative. No Kimmelstiel-Wilson nodules were seen. Immunofluorescence (IF) demonstrated diffuse granular capillary and mesangial staining for IgG (3+), C3 (2+), IgA (1+), C1q (trace), kappa (4+) and lambda (4+). IF staining for M-type PLA2R showed 3+ diffuse, granular staining predominantly in subepithelial distribution. EM showed segmental mild BM thickening and subepithelial granular deposits with diffuse effacement of foot processes (>90%). In addition, there were regions of mesangial and para-mesangial intramembranous non-branching fibrillary deposits, 12-28nm in diameter. The renal disease was treated with furosemide, lisinopril, prednisone, and tacrolimus with improvement in proteinuria and lower extremity edema. CIDP was treated with IVIG. The patient is currently in clinical remission with stable CKD4.
Discussion
While FGN may have granular subepithelial deposits that mimic MN, positivity for anti-PLA2R is unique, suggesting dual glomerulopathy with coincidental Primary MN. FGN associated with MN in the setting of CIDP is very rare. More studies are needed to help understand these complex associations.