1. ¹Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
2. ²Nephrology Section, University of Chicago, Chicago, Illinois, USA
3. ³International Kidney Stone Institute, Methodist Clarian Hospital, Indianapolis, Indiana, USA
4. ⁴Department of Histology, Jinzhou Medical College, Jinzhou, Liaoning, People's Republic of China
5. ⁵Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA
6. ⁶Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Canada
7. ⁷Department of Pathology, Indiana University School of Medicine, Indianapolis, Indiana, USA

Correspondence: AP Evan, Department of Anatomy and Cell Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS 5055, Indianapolis, Indiana 46220, USA. E-mail: evan@anatomy.iupui.edu

Received 4 November 2005; Revised 6 December 2005; Accepted 23 December 2005; Published online 17 May 2006.

Abstract

We have biopsied the papillae of patients who have cystine stones asking if this stone type is associated with specific tissue changes. We studied seven cystine stone formers (SF) treated with percutaneous nephrolithotomy using digital video imaging of renal papillae for mapping and obtained papillary biopsies. Biopsies were analyzed by routine light and electron microscopy, infrared spectroscopy, electron diffraction, and micro-CT. Many ducts of Bellini (BD) had an enlarged ostium, and all such were plugged with cystine crystals, and had injured or absent lining cells with a surrounding interstitium that was inflamed to fibrotic. Crystal plugs often projected into the urinary space. Many inner medullary collecting ducts (IMCD) were dilated with or without crystal plugging. Apatite crystals were identified in the lumens of loops of Henle and IMCD. Abundance of interstitial Randall's plaque was equivalent in amount to that of non-SF. In the cortex, glomerular obsolescence and interstitial fibrosis exceeded normal. Cystine crystallizes in BD with the probable result of cell injury, interstitial reaction, nephron obstruction, and with the potential of inducing cortical change and loss of IMCD tubular fluid pH regulation, resulting in apatite formation. The pattern of IMCD dilation, and loss of medullary structures is most compatible with such obstruction, either from BD lumen plugs or urinary tract obstruction from stones themselves.