Normal H&E Distal tubule Capillary loop Capillary loops are patent Mesangial cell (not more than 3 adjacent to each other…if >3: mesangial hypercellularity) Proximal convoluted tubule (foamy cytoplasm) This may be an endothelial or a mesangial cell (no problem)

Normal PAS Positive = fuchsia color as the color of basement membranes here This is the normal thicknes of GBM as highlighted by PAS…try to train your eyes on this thickness As you see: the BM surrounding every thing is well-highlighted by PAS Visceral epithelial cells

GBM Blood Normal EM Podocyte (visceral epithelial cell) foot process Slit diaphragm …the area is called: filtration slit Blood A fenestration in endothelial cell

RBC When we see this change alone without LM or IF change: Minimal change disease Effaced foot process GBM RBC

Example of FSGS …H&E Eosinophilic material (fibrosis) that effaced the capillary loops…as you see just the change is in a segment of glomerulus…= segmental sclerosis Hyaline mass…may accompany FSGS…may resemble fibrin

Example of FSGS …Masson trichrome stain …collagen is blue The fibrosis appears bluish in color …again this is segmental sclerosis

A case of poststreptococcal GN…H&E Lobulation neutrophils Enlargement & lobulation of the glomerulus + proliferation of all cells in the area + inflammatory cells…this proliferation causes capillary loops to be closed…this appearance can be seen in postinfectious glomerulonephritis and in MPGN1/DDD…the presence of neutrophils may be a hint for poststrept. GN

Higher power of image in slide 7

Formed of IgG & C3 Poststreptococcal glomerulonephritis Subepithelial hump (between the GBM and the podocyte) Foot process (Capillary lumen)

IF: A case of membranous nephropathy: granular capillary pattern

H&E A case of membranous nephropathy…in this example, the abnormality seen is just GBM thickening Thickened GBM

Membranous nephropathy (silver stain) Silver stains BM black Spikes (processes of GBM that are formed as a reaction to subepithelial deposits)…best seen by silver, but may also by PAS or even H&E by expert eyes)

Membranous nephropathy

IF: A case of membranous nephropathy: granular capillary pattern

IF: A case of membranous nephropathy: granular capillary pattern

Crescentic GN (a change that can be seen in many diseases especially those that cause rapidly progressive GN) …this is PAS stain Proliferation of parietal cells + macrophages as a crescent In this case it is early crescent (cellular crescent)

H&E Crescent…in this example it is somewhat late crescent (started to become fibrosed…fibrous crescent)

IF: linear capillary pattern (anti-GBM antibody/Goodpasture syndrome)

H&E Mesangial hypercellularity (more than 3 adjacent mesangial cells) A nonspecific change but remember it very well in IgA nephropathy

IF: granular mesangial pattern

IF: granular mesangial pattern

H&E: A case of membranoproliferative Glomerulonephritis 1 or DDD (dense deposit disease) Enlargement + proliferation of all cells in the area + inflammatory cells…this proliferation causes capillary loops to be closed…this appearance can be seen in postinfectious glomerulonephritis and in MPGN1/DDD…the presence of neutrophils may be a hint for poststrept. GN …no neutrophils here (but still this can be seen In poststrep.)

MPGN1 or DDD…silver stain Tram track appearance (2 lines draw the GBM)…best seen by silver (as in this case) MPGN1 or DDD…silver stain

Thank You