
- Published: January 9, 2018
- By: Alejandro Best, MD and Arkana Author
- Tags: Amyloidosis, Apolipoprotein A-IV amyloidosis, Congo red, Progressive renal failure, Rare renal disease
This renal biopsy from a 71-year-old female, who presented with progressively worsening renal failure, shows unremarkable glomeruli by light microscopy (Fig 1), with minimal associated tubulointerstitial chronic injury. Of note, multifocal PAS-pale, weakly argyrophilic, Congo red positive (Fig 2) deposits with apple green birefringence (Fig 3), consistent with amyloid deposits, are present exclusively within the interstitium of the renal medulla. No amyloid deposition is present within the renal cortex or involving vascular structures. The deposits show no light chain restriction by routine or paraffin immunofluorescence (not shown), making the possibility of light chain-type amyloidosis unlikely. Furthermore, an immunoperoxidase stain for...