Congenital renal glomerular fibrosis in a case of swine chondrodysplasia.

A dwarf male Large White neonate showing various external abnormalities was diagnosed to be chondrodysplasia. Microscopy revealed massive accumulation of eosinophilic homogeneous substance in the renal glomeruli, mainly along the capillary walls. The homogeneous substance, mainly consisted of type-III collagen, was not found in the primitive glomeruli in the superficial cortex, and was most frequently and intensely deposited in the mature glomeruli in the deep cortex. Electron microscopically, the deposits consisted of the collagen fibrils with various structural abnormalities. Glomerular fibrosis might be attributed to in situ production of type-III collagen by glomerular cells with differentiation and maturation, most likely by the mesangial cells.