Membranous glomeruopathy

Question 1

Definition of MGN

Answer 1

Glom capillary wall abnormalities resulting from subepithelial immune deposits

Diffuse thickening of glom capillary wall thickening

Not characteristically ass with hypercellularity or inflammation

Question 2

Clinical course

Answer 2

Clinically often proteinuria, but no specific clinical features

Proteinuria often severe, with nephrotic syndrome and thrombotic tendency

Non-selective proteinuria

Haematuria

Hypertension

Question 3

Histology of membranous glomerulopathy

Answer 3

Stage 1: Sub-endothelial depositis of IF. NO thickening of glom capillary walls on H+E. Enlarged, distended capillary lumens. Tubular epithelial cells contain resorption droplets

Stage 2: Thickened, rigid glomerular capillary walls, Diffuse, global. Special stains show basement membrane spikes separating subepithelial deposits (cut en face look like swiss cheese). Diffuse podocyte swelling.

Stage 3: Thickened glomerular capillary walls, narrowing of lumens. Deposits intramembranous, formation of neomembrane - appears tram-track on silver stain. Mild mesangial sclerosis. Some gloms may show segmental/global sclerosis. Interstitial foam cells.

Stage 4: Marked thickening of glom capillary walls, widespread segmental and global glomerulosclerosis. Spikes difficult to see. Deposits hard to see as resorption has taken place. Mesangial sclerosis. Advanced tubular atrophy and interstitial fibrosis.

Question 4

IF