Staging criteria for renal cell carcinoma differ from many other cancers, in that renal tumors are often spherical with subtle, finger-like extensions into veins, renal sinus, or perinephric tissue. We sought to study interobserver agreement in pathologic stage categories for challenging cases. An online survey was circulated to urologic pathologists interested in kidney tumors, yielding 89% response (31/35). Most questions included 1 to 4 images, focusing on: vascular and renal sinus invasion (n=24), perinephric invasion (n=9), and gross pathology/specimen handling (n=17). Responses were collapsed for analysis into positive and negative/equivocal for upstaging. Consensus was regarded as an agreement of 67% (2/3) of participants, which was reached in 20/33 (61%) evaluable scenarios regarding renal sinus, perinephric, or vein invasion, of which 13/33 (39%) had ≥80% consensus. Lack of agreement was especially encountered regarding small tumor protrusions into a possible vascular lumen, close to the tumor leading edge. For gross photographs, most were interpreted as suspicious but requiring histologic confirmation. Most participants (61%) rarely used special stains to evaluate vascular invasion, usually endothelial markers (81%). Most agreed that a spherical mass bulging well beyond the kidney parenchyma into the renal sinus (71%) or perinephric fat (90%) did not necessarily indicate invasion. Interobserver agreement in pathologic staging of renal cancer is relatively good among urologic pathologists interested in kidney tumors, even when selecting cases that test the earliest and borderline thresholds for extrarenal extension. Disagreements remain, however, particularly for tumors with small, finger-like protrusions, closely juxtaposed to the main mass.
The American journal of surgical pathology. 2018 Jun 06 [Epub ahead of print]
Sean R Williamson, Priya Rao, Ondrej Hes, Jonathan I Epstein, Steven C Smith, Maria M Picken, Ming Zhou, Maria S Tretiakova, Satish K Tickoo, Ying-Bei Chen, Victor E Reuter, Stewart Fleming, Fiona M Maclean, Nilesh S Gupta, Naoto Kuroda, Brett Delahunt, Rohit Mehra, Christopher G Przybycin, Liang Cheng, John N Eble, David J Grignon, Holger Moch, Jose I Lopez, Lakshmi P Kunju, Pheroze Tamboli, John R Srigley, Mahul B Amin, Guido Martignoni, Michelle S Hirsch, Stephen M Bonsib, Kiril Trpkov
Department of Pathology and Laboratory Medicine, Henry Ford Cancer Institute, Henry Ford Health System., University of Texas MD Anderson Cancer Center, Houston., Department of Pathology, University Hospital Plzen, Charles University, Plzen, Czech Republic., Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD., Department of Pathology, VCU School of Medicine, Richmond, VA., Department of Pathology, Loyola University Medical Center, Maywood, IL., Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX., Department of Pathology, University of Washington, Seattle, WA., Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY., Department of Pathology, University of Dundee, Dundee, UK., Douglass Hanly Moir Pathology, Sydney, NSW, Australia., Department of Diagnostic Pathology, Kochi Red Cross Hospital, Kochi City, Kochi, Japan., Department of Pathology, University of Otago, Wellington, New Zealand., Department of Pathology, University of Michigan, Ann Arbor, MI., Department of Pathology, Cleveland Clinic Robert J Tomsich Pathology and Laboratory Medicine Institute, Cleveland, OH., Department of Pathology, Indiana University School of Medicine, Indianapolis, IN., Department for Pathology and Molecular Pathology, University and University Hospital Zurich, Zurich, Switzerland., Cruces University Hospital, Biocruces Institute, University of the Basque Country, Barakaldo, Spain., Trillium Health Partners, Mississauga, ON., Department of Pathology, University of Tennessee Health Science Center, Memphis, TN., Hospital Pederzoli-Verona, and Department of Diagnostics and Public Health, University of Verona, Verona, Italy., Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA., Arkana Laboratories, Little Rock, AK., University of Calgary and Calgary Laboratory Services, Calgary, AB, Canada.