Role of Interstitial Apatite Plaque in the Pathogenesis of the Common Calcium Oxalate Stone

Andrew P. Evan, James E. Lingeman, Fredric L. Coe, Elaine M. Worcester

Research output: Contribution to journalArticle

38 Scopus citations


Summary: By using intraoperative papillary biopsy material from kidneys of idiopathic calcium oxalate, intestinal bypass for obesity, brushite, cystine, and distal renal tubular acidosis stone formers during percutaneous nephrolithotomy, we have determined that idiopathic calcium oxalate stone formers appear to be the special case, although the most commonly encountered one, in which stones form external to the kidney and by processes that do not involve the epithelial compartments. It is in this one group of patients that we find not only abundant interstitial plaque, but also strong evidence that the plaque is essential to stone formation. The initial site of plaque formation is always in the papillary tip, and must be in the basement membrane of the thin loop of Henle. With time, plaque spreads throughout the papilla tip to the urothelium, which under conditions we do not understand is denuded and thereby exposes the apatite deposits to the urine. It is on this exposed apatite that a stone forms as an overgrowth, first of amorphous apatite and then layers of calcium oxalate. This process generates an attached stone fixed to the side of a papilla, allowing the ever-changing urine to dictate stone growth and composition.

Original languageEnglish (US)
Pages (from-to)111-119
Number of pages9
JournalSeminars in nephrology
Issue number2
StatePublished - Mar 1 2008


  • hyaluronan
  • Loops of Henle
  • papillary biopsies

ASJC Scopus subject areas

  • Nephrology

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