46-year-old female suffered from a nephrotic syndrome and mild hematuria. She later developed renal hypertension (specimen from autopsy).
- Almost all glomeruli are affected.
- Increase in mesangial matrix and mild mesangial hypercellularity.
- The glomerular basement membrane is diffusely thickened and in part reduplicated. Some reddish- violet subendothelial deposits can be seen by light microscopy (SFOG stain).
- Isolated synechias between the Bowman's capsule and the glomerular capillary loops are observed.
- Ultimately, glomeruli become completely hyalinized.
- The interstitium exhibits in part a marked fibrosis. In fibrotic areas a non-specific lymphocytic infiltrate is seen. Tubuli are atrophic with a thickened, undulated and often split basement membrane. Some tubuli contain protein cylinders.
- Small- and medium sized arteries with wall-thickening.
Definition: Membranoproliferative glomerulonephritis (type I) is characterized by a combination of mesangial cell proliferation and capillary wall-thickening.
Pathogenesis: Type III hypersensitivity (immune complex-mediated). Subendothelial deposits of immune-complexes lead to activation of both classical and alternative complement pathways.