Introduction:
Fibrillary glomerulonephritis (FGN) is a rare proliferative form of glomerular disease characterized by randomly oriented fibrillar deposits with a mean diameter of 20 nm. By immunofluorescence (IF), the deposits stain for IgG, C3, and κ and λ light chains, suggesting that the fibrils may be composed of antigen-antibody immune complexes. Recently, a highly sensitive and specific tissue marker for FGN, DNAJB9 has been identified. The morphological features vary from membranous, mesangial-proliferative, endo-capillary proliferative to crescentic glomerulonephritis. Membranous pattern fibrillary GN cases often misdiagnosed as MGN. Co-existence of membranous pattern glomerulopathy and fibrillary GN can also complicate the diagnosis of Fibrillary GN. First time, we report three cases of fibrillary GN with coexisting membranous pattern glomerulopathy.
Methods:
Three cases diagnosed with coexisting with Fibrillary GN with membranous pattern glomerulopathy were included in present study
Results:
Case1- Case of 39 year male diagnosed with membranous nephropathy, treated appropriately, 6 year later, due to persistent nephrotic range proteinuria, re-biopsy was done. Light microscopy show membranous pattern GN with focal endo-capillary hyper cellularity and focal crescent formation, DIF studies show capillary wall granular and mesangial smudgy staining for IgG, c1q, kappa or lambda. IHC for DNAJB9 was positive in glomeruli and focally along TBM. Target antigen PLA2R, NELL-1, Thombospondin, Exostosin and Semaphorin3B were negative. On ultrastructural examination conventional immune complex type subepithelial electron dense deposit with co-existing capillary wall and mesangial fibrils with mean diameter of 20 nm were noted.
Case 2-This is case of 54 year old female patient presented with DM, HTN, Nephrotic syndrome, S. creatinine of 2.08mg/dl and serum PLA2R level >1500. Biopsy showed Membranous pattern nephropathy, DIF studies showed capillary wall granular to smudgy immune staining for IgG, Kappa and lambda. IHC for DNAJB9 and PLA2R were positive in glomeruli.
Case 3-This is case of 48 year female presented with proteinuria, diagnosed with membranous GN, on ultrastructural examination few conventional immune complex type electron dense deposit in sub epithelial and sub endothelial region coexisting with aggregate of fibrils with mean diameter of 18.3nm were noted. Two years later in view of persistent proteinuria, re-biopsy was done, now ultrastructural examination showed increase in number of electron dense deposit in sub epithelial region with coexisting mesangial and intramembranous fibrils (Mean diameter-20 nm)
Conclusions:
First time, we report three cases of fibrillary GN coexisting with Membranous pattern glomerulopathy. This case series highlight the importance of careful assessment of DIF staining pattern smudgy to confluent co-existing with fine granular staining pattern along GBM in cases of Membranous nephropathy, so that we dont miss rare diagnosis of coexisting fibrillary GN with membranous pattern glomerulopathy.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.