Nephrotic syndrome with focal segmental glomerular lesions unclassified by Columbia classification; Pathology and clinical implication
Fig 2
Pathological findings in patients who did not fit any of the FSGS variants in the Columbia classification: The unclassified group.
(A and B) Typical finding of “endothelial damage” by PAM staining. The patients had findings suggesting endothelial damage, i.e., mesangiolysis and/or double contour of the glomerular basement membrane without endocapillary occlusion or matrix accumulation. (C and D) The finding of “simple attachment” by PAM staining. The image indicates small fibrous synechia to the Bowman capsule without any endocapillary or extracapillary interactions. The patients had no other findings on FSGS. (E and F) The finding of “minor cellular lesion” by PAM staining. The image indicates cellular occlusion of the glomerular capillaries by foam cell(s), but with a distribution of less than 25% of the tuft. The patients had no other findings on FSGS. A, C, and E are at ×400 magnification with PAM staining, and B, D, and F are at ×1000 magnification with PAM staining. Abbreviations: FSGS, Focal segmental glomerulosclerosis; PAM, Periodic acid methenamine silver stain.