Collapsing Glomerulopathy in Lambda Light Chain Amyloidosis: A Report of 2 Cases  Mazdak A. Khalighi, Alexander J. Gallan, Anthony Chang, Shane M. Meehan  American Journal of Kidney Diseases  Volume 72, Issue 4, Pages 612-616 (October 2018) DOI: 10.1053/j.ajkd.2018.04.009 Copyright © 2018 National Kidney Foundation, Inc. Terms and Conditions

Figure 1 Kidney biopsy specimen from case 1. (A) There was extensive infiltration of glomeruli by an acellular amorphous material that stained weakly by periodic acid–Schiff (PAS), was silver negative, and showed strong staining on Congo Red study. (B) Focally, there was prominent epithelial cell hyperplasia with associated glomerular collapse and apparent segmental glomerular basement membrane (GBM) disruption (arrow) (Jones methenamine silver). (C) Vascular deposition of amyloid was prominent (PAS) with focally marked arteriolar luminal compromise (arrow). Immunofluorescence microscopy showed (D) prominent staining for λ light chain (E) without concurrent staining for κ light chain. (F) Ultrastructural examination showed accumulation of fibrils within the glomerulus that segmentally protruded into the urinary space abutting the overlying podocytes (arrowhead highlights apparent GBM disruption). American Journal of Kidney Diseases 2018 72, 612-616DOI: (10.1053/j.ajkd.2018.04.009) Copyright © 2018 National Kidney Foundation, Inc. Terms and Conditions

Figure 2 Kidney biopsy specimen from patient 2. (A) There was prominent accumulation of an acellular material within glomerular, interstitial, and vascular compartments that was diffusely positive on Congo Red stain. (B) The material in this case was weakly positive on silver stain and glomeruli focally showed prominence of overlying epithelial cells and associated segmental sclerosis of the glomerular tuft (Jones methenamine silver). Rare epithelial mitotic figures were identified (arrowhead), as were rare segments with apparent glomerular basement membrane (GBM) disruption (arrow). (C) Vascular deposition was diffusely present and a few glomeruli with collapsing features also showed marked amyloid accumulation at the vascular hilum (arrow; periodic acid–Schiff). Similar to case 1, (D) deposits were λ light chain–restricted (E) without staining for κ light chain. (F) Ultrastructural examination showed frequent amyloid “spicules” protruding from the GBM with associated protrusion against the podocyte cell bodies (seen best on tangential sectioning). American Journal of Kidney Diseases 2018 72, 612-616DOI: (10.1053/j.ajkd.2018.04.009) Copyright © 2018 National Kidney Foundation, Inc. Terms and Conditions