1. Collapsing glomerulopathy.
Collapsing glomerulopathy. (A) Transplant biopsy in a patient with CG secondary to thrombotic microangiopathy. Segmental collapse and pseudocrescent formation are present (arrows) (Silver stain). (B) The proliferative marker Ki67 is detected in podocyte nuclei in this 2-yr-old patient with CG associated with COQ2 mutation (immunoperoxidase). (C) Electron microscopy shows podocytes overlying mildly wrinkled glomerular basement membrane (GBM). The podocytes have lost both primary processes andfoot processes (arrows). Podocytes are separated from the original GBM by newly formed extracellular matrix (*). (D) Dedifferentiated podocytes re-express other proteins that are normally expressed only during development, such as cytokeratin (immunoperoxidase). Magnifications: ×40 in A; ×60 in B and D; ×5000 in C.
Laura Barisoni et al. CJASN 2007;2:
©2007 by American Society of Nephrology