Segmental obliteration of the glomerular capillary lumen in a patient with FSGS. Note the sclerotic portion of the glomerular tuft is adherent to Bowman’s capsule. There is proximal tubular hypertrophy, which can be seen in this condition in response to heavy proteinuria.
The glomerular capillary bed is thickened, with the presence of double contours reflecting circumferential mesangial expansion into the capillary wall (mesangial interposition). In this biopsy core of chronic allograft injury there is minimal interstitial inflammation, primarily localized to the areas of tubular atrophy, and severe interstitial fibrosis.