We report the case of a white woman with bilateral renal calculi that were removed by
bilateral nephrolithotomies. The morphology of renal tubular stones and the changes in
papillary tissue were studied by light microscopy and scanning and transmission electron
microscopy. The stones were made of calcium oxalate and were intratubular. Large calcium
phosphate deposits were present in the interstitium. There was a marked interstitial fibrosis
and tubular epithelial hyperplasia.