Desmosomes as markers for the proliferating parietal epithelial cells in collapsing glomerulosclerosis. A case report

Two variants of focal segmental glomerulosclerosis are known to present epithelial hypercellularity in the Bowman's space, namely the collapsing and the cellular types. This epithelial cell proliferation may get features of either pseudocrescent or tubular profiles. Our case of collapsing focal segmental glomerulosclerosis has been ultrastructurally investigated concerning the proliferating epithelial cell type: parietal versus visceral. Based on the cellular organelles, especially on the ubiquitous presence of desmosomes, the authors are endorsing, with ultrastructural arguments, the opinion favoring the parietal epithelial cells (PEC) as the proliferating cell type. It is also taken into consideration the eventual change of PECs phenotype in contact with the glomerular tuft components like the glomerular basement membrane.