Metabolic and urinary risk factors associated with Randall's papillary plaques

Background and Purpose: Increasing evidence suggests that Randall's plaques contribute to the pathogenesis of urinary stone formation. The purpose of our study was to evaluate the urinary risk factors of stone patients who underwent endoscopic mapping of their calices for Randall's plaques. Patients and Materials: Patients (N = 143) having endoscopic procedures to remove upper tract calculi or for other purposes underwent mapping of their calices for Randall's plaques. Plaque incidence and pattern were correlated with the stone composition and urinary risk factors found on subsequent metabolic evaluation. Results: Papillary plaques were found more commonly in patients having calcium oxalate stones than in patients with other stone types and patients without a history of stones. Papillary plaque incidence and pattern did not correlate with any specific urinary risk factor; however, patients with plaques tended to exhibit a higher incidence of all risk factors. Plaque severity tended to be greater in patients exhibiting hypercalciuria. Conclusions: Randall's plaques are found most frequently in patients with calcium oxalate stones and are most important in the pathogenesis of calcium oxalate nephrolithiasis. Stone patients with papillary plaques are more likely to exhibit abnormalities in their urinary milieu than are patients without papillary plaques.