On kidney biopsy, PAS-positive structures are:

To analyse the glomerulus, the PAS stain is most useful, since it delineates in great detail glomerular cells, mesangial matrix and potential expansion, as well as potential modifications of the composition of the matrix, changes of the GBM, i.e. thickening, irregularities, doubling, rupture and finally fibrinoid necrosis of the glomerular tuft. A fuher advantage of the PAS stain is that alterations of the vessels, paicularly aerial hyalinosis and fibrinoid necrosis, are easy to detect. Ref: academic.oup.com