Fibronectin non-amyloid glomerulopathy.
A 41-year-old Burmese man presented with nephrotic syndrome, a creatinine level of 150 micromol/L and limited clinical history. His renal biopsy demonstrated glomerulopathy with large eosinophilic deposits in the mesangium and capillary loops that were negative for Congo red, slightly positive for periodic acid-Schiff and blue with Masson trichrome stain. Immunofluorescence microscopy with a routine antibody panel was unhelpful. Electron microscopy demonstrated extensive, moderately electron-dense deposits in the subendothelial space, subepithelial space and mesangium that could be differentiated from adjacent basement membrane by their increased electron density. The deposits contained finely granular material and occasional filaments with variable diameter ranging from 9-16 nm. Fibronectin glomerulopathy was suspected from anti-fibronectin immunohistochemistry that showed positive staining of thickened capillary loops. This staining was subsequently confirmed by immunoelectron microscopy demonstrating the presence of cellular fibronectin (cFN) in deposits. Significantly, deposition of fibronectin appeared to have occurred in the absence of thickening or folding of the adjacent basement membrane. The prominent mesangial location of deposits containing a cFN isotype may indicate that retention of local fibronectin produced in the mesangium has contributed to this pathology.
Yong
Jim L
JL
Department of Anatomical Pathology, South Western Area Pathology Service, Liverpool NSW, Australia.
Killingsworth
Murray C
MC
Spicer
S Timothy
ST
Wu
Xiao-Juan
XJ
D000328:Adult; D001485:Basement Membrane / Q000378:metabolism / Q000648:ultrastructure; D001706:Biopsy; D005353:Fibronectins / Q000378:metabolism*; D005500:Follow-Up Studies; D005920:Glomerular Mesangium / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000378:metabolism* / Q000473:pathology; D007678:Kidney Glomerulus / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D016253:Microscopy, Immunoelectron; D009404:Nephrotic Syndrome / Q000473:pathology; D013997:Time Factors
D005353:Fibronectins