Fig. 2

Microscopic observation of Pizzolato-stained calcium oxalate crystal deposits in the renal cortex, medulla, and papilla of stone formers (SFs) and non-stone formers (NSFs). a In the renal cortex, the crystals were located in the tubular lumen and attached to the walls. b In the medullary region, the crystal-attached tubular epithelial cells were abraded and crystal transmigration into the interstitium was observed. (c) In the papillary region, almost all the crystals were detected in the interstitium. Arrows indicate tubules with crystal deposits