The American Journal of Surgical Pathology
Special Articles
The International Society of Urological Pathology (ISUP) Grading System for Renal Cell Carcinoma and Other Prognostic Parameters
Delahunt, Brett MD*; Cheville, John C. MD†; Martignoni, Guido MD‡; Humphrey, Peter A. MD§; Magi-Galluzzi, Cristina MD∥; McKenney, Jesse MD∥; Egevad, Lars MD¶; Algaba, Ferran MD#; Moch, Holger MD**; Grignon, David J. MD††; Montironi, Rodolfo MD‡‡; Srigley, John R. MD§§,∥∥ The Members of the ISUP Renal Tumor Panel
*Department of Pathology and Molecular Medicine, Wellington School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand
†Department of Pathology, Mayo Clinic, Rochester, MN
§Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO
∥Department of Anatomic Pathology, Cancer Biology and Glickman Urological Institute, Cleveland, OH
††Department of Pathology, Indiana University School of Medicine, Indianapolis, IN
‡Dipartimento di Patologia e Diagnostica, Universitá di Verona, Verona
‡‡The Institute of Pathological Anatomy and Histopathology, University of Ancona School of Medicine, Ancona, Italy
¶Department of Oncology and Pathology, Karolinska University Hospital, Solna, Stockholm, Sweden
#Department of Pathology, Fundacion Puigvert-University Antonomous, Barcelona, Spain
**University of Zurich, Switzerland
§§Department of Laboratory Medicine, Credit Valley Hospital, Mississauga
∥∥Department of Pathology and Molecular Medicine, McMaster University, Toronto, ON, Canada
Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article.
Correspondence: Brett Delahunt, MD, Department of Pathology and Molecular Medicine, Wellington School of Medicine and Health Sciences, University of Otago, 23A Mein St, Wellington, 6021, New Zealand (e-mail: [email protected]).
Abstract
The International Society of Urological Pathology 2012 Consensus Conference made recommendations regarding classification, prognostic factors, staging, and immunohistochemical and molecular assessment of adult renal tumors. Issues relating to prognostic factors were coordinated by a workgroup who identified tumor morphotype, sarcomatoid/rhabdoid differentiation, tumor necrosis, grading, and microvascular invasion as potential prognostic parameters. There was consensus that the main morphotypes of renal cell carcinoma (RCC) were of prognostic significance, that subtyping of papillary RCC (types 1 and 2) provided additional prognostic information, and that clear cell tubulopapillary RCC was associated with a more favorable outcome. For tumors showing sarcomatoid or rhabdoid differentiation, there was consensus that a minimum proportion of tumor was not required for diagnostic purposes. It was also agreed upon that the underlying subtype of carcinoma should be reported. For sarcomatoid carcinoma, it was further agreed upon that if the underlying carcinoma subtype was absent the tumor should be classified as a grade 4 unclassified carcinoma with a sarcomatoid component. Tumor necrosis was considered to have prognostic significance, with assessment based on macroscopic and microscopic examination of the tumor. It was recommended that for clear cell RCC the amount of necrosis should be quantified. There was consensus that nucleolar prominence defined grades 1 to 3 of clear cell and papillary RCCs, whereas extreme nuclear pleomorphism or sarcomatoid and/or rhabdoid differentiation defined grade 4 tumors. It was agreed upon that chromophobe RCC should not be graded. There was consensus that microvascular invasion should not be included as a staging criterion for RCC.