WCE 2018: Intrarenal Calcifications – Prospective Phenotypic Characterization by Endoscopic and Histologic Quantification

Paris, France (UroToday.com) Interstitial Randall’s plaques and duct of Bellini plugs are two calcium-phosphate-based renal papillary pathologies. Plaques and plugs are thought to be precursors to urinary stone formation, though the exact pathogenesis remains unclear. Dr. Agarwal and his colleagues at Mayo Clinic, Rochester sought to contribute to the current body of knowledge regarding this topic by studying for any associations between papillary pathology and patient demographics, stone type, and urinary chemistry.

The investigators prospectively evaluated 295 patients undergoing percutaneous nephrolithotomy (PCNL) using pre- and post-operative computed tomography (CT), papillary biopsy, postoperative stone analysis, and 24-hour urine collection.

Notably, nearly all (94%) of patients had plaques in at least 1 papilla, while nearly 16% of patients had significant plugging. Patients with apatite stones demonstrated the largest percentage of surface area plugging. A few significant associations between patient demographics and stone type were found and are summarized in the table below. 

UroToday WCE2018 Intrarenal Calcifications Prospective Phenotypic Characterization by Endoscopic And Histologic Quantification

One audience member asked a thought-provoking question regarding the potential for intra-operative papillary biopsy to substitute for 24-hour urine collection as a means by which to evaluate patients’ stone- forming etiologies. While Dr. Agarwal acknowledged that his group’s findings may help lay the foundation for better understanding the pathogenesis of stone formation, he stated that more data are needed before we transition away from such a staple of stone former workup as 24-hour urine collection.

Presented by: Deepak Agarwal, MD, Resident Physician, Mayo Clinic, Rochester, Minnesota1
Co-Authors: Felicity Enders1, Ramila Mehta1, Lisa Vaughan1, Terri Vrtiska1, Loren Herrera Hernandez1, David Holmes1, Andrew Rule1, John Lieske1, Professor Amy Krambeck2 , Assistant Professor Marcelino Rivera1

Author Affiliation: 
1. Mayo Clinic (Rochester), Rochester, Minnesota, USA
2. Indiana University School of Medicine, Indianapolis, Indiana, USA

Written by: Frank Jefferson, Department of Urology, University of California-Irvine, medical writer for UroToday.com at the 36th World Congress of Endourology (WCE) and SWL - September 20-23, 2018 Paris, France