Kidney non-tumor - Fibrillary glomerulonephritis

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Kidney non-tumor

Primary glomerular diseases

Fibrillary glomerulonephritis

Reviewers: Nikhil Sangle, M.D. (see Reviewers page)
Revised: 17 April 2012, last major update April 2012
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.

General
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● Not a disease, but the morphologic expression of a diverse group of diseases incompletely defined (Hum Pathol 2001;32:660)
● Deposition of extracellular non-amyloid fibrillary material in glomerular basement membranes, mesangium and tubular basement membranes (“nephropathy” better term than glomerulonephritis)

Clinical features
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● Rare, < 1% of renal biopsies
● More common in whites and females
● Associated with malignancy (most commonly carcinoma), dysproteinemia, autoimmune disease
● Patients present with heavy proteinuria, hematuria, renal insufficiency, systemic hypertension
● 50% develop end-stage kidney disease within 2-4 years from diagnosis
● No evidence of extrarenal fibrillary deposits
● Features overlap with hepatitis C virus induced cryoglobulinemic glomerulonephritis
● Diagnosis: based on ultrastructural (EM) findings; some authors require exclusion of cryoglobulins

Treatment
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● Kidney transplantation appears safe, with low risk of recurrence; in contast, patients with monoclonal gammopathy with fibrillary deposits have a significant risk for post-transplant recurrence (Kidney Int 2009;75:420)
● Treatment with rituximab may be helpful (Am J Kidney Dis 2008;52:1158)

Case reports
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● 43 year old man with polyclonal gammopathy but IgG1 deposits (Mod Pathol 1998;11:103)
● 50 year old man (Arch Pathol Lab Med 2001;125:534)

Micro description
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● Most common histologic patterns are mesangial proliferative / sclerosing followed by membranoproliferative glomerulonephritis (Clin J Am Soc Nephrol 2011;6:775)
● Mesangial expansion with PAS-positive material, diffuse thickening of the glomerular basement membrane
● Variable proliferative lesions, 25% have crescents (Am J Kidney Dis 2012 Mar 5 [Epub ahead of print])
● Silver stain highlights thickening of basement membrane and mesangial expansion by material that has a distinct ‘motheaten’ appearance (due to silver-negative deposits)

Micro images
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Fibrillary glomerulonephritis

Case with crescents

Various images

IgG immunofluorescence

Immunofluorescence
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● Glomerular capillary wall and mesangial deposition of IgG4, C3, kappa and lambda light chains

Electron microscopy description
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● Randomly arranged non-amyloid fibrils in the mesangium and glomerular capillary walls, 18-22 nm thick vs. 10 nm thick fibrils for amyloid and 30-50 nm thick organized tubules for immunotactoid glomerulopathy
● Usually extensive effacement of epithelial foot processes

Electron microscopy images
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Randomly oriented subepithelial fibrils

Fibrillar deposits in the mesangium

Series of images

End of Kidney non-tumor > Primary glomerular diseases > Fibrillary glomerulonephritis

Ref Updated: 4/16/12

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