Renal medullary carcinomas (RMCs) and collecting duct carcinomas (CDCs) are rare subsets of lethal high-stage, high-grade distal nephron-related adenocarcinomas with a predilection for the renal medullary region. Recent findings have established an emerging group of fumarate hydratase (FH)-deficient tumors related to hereditary leiomyomatosis and renal cell carcinoma (HLRCC-RCCs) syndrome within this morphologic spectrum. Recently developed, reliable ancillary testing has enabled consistent separation between these tumor types. Here, we present the clinicopathologic features and differences in the morphologic patterns between RMC, CDC, and FH-deficient RCC in consequence of these recent developments. This study included a total of 100 cases classified using contemporary criteria and ancillary tests. Thirty-three RMCs (SMARCB1/INI1-deficient, hemoglobinopathy), 38 CDCs (SMARCB1/INI1-retained), and 29 RCCs defined by the FH-deficient phenotype (FH/2SC or FH/2SC with FH mutation, regardless of HLRCC syndromic stigmata/history) were selected. The spectrum of morphologic patterns was critically evaluated, and the differences between the morphologic patterns present in the 3 groups were analyzed statistically. Twenty-five percent of cases initially diagnosed as CDC were reclassified as FH-deficient RCC on the basis of our contemporary diagnostic approach. Among the different overlapping morphologic patterns, sieve-like/cribriform and reticular/yolk sac tumor-like patterns favored RMCs, whereas intracystic papillary and tubulocystic patterns favored FH-deficient RCC. The tubulopapillary pattern favored both CDCs and FH-deficient RCCs, and the multinodular infiltrating papillary pattern favored CDCs. Infiltrating glandular and solid sheets/cords/nested patterns were not statistically different among the 3 groups. Viral inclusion-like macronucleoli, considered as a hallmark of HLRCC-RCCs, were observed significantly more frequently in FH-deficient RCCs. Despite the overlapping morphology found among these clinically aggressive infiltrating high-grade adenocarcinomas of the kidney, reproducible differences in morphology emerged between these categories after rigorous characterization. Finally, we recommend that definitive diagnosis of CDC should only be made if RMC and FH-deficient RCC are excluded.
The American journal of surgical pathology. 2018 Jan 05 [Epub ahead of print]
Chisato Ohe, Steven C Smith, Deepika Sirohi, Mukul Divatia, Mariza de Peralta-Venturina, Gladell P Paner, Abbas Agaimy, Mitual B Amin, Pedram Argani, Ying-Bei Chen, Liang Cheng, Maurizio Colecchia, Eva Compérat, Isabela Werneck da Cunha, Jonathan I Epstein, Anthony J Gill, Ondřej Hes, Michelle S Hirsch, Wolfram Jochum, Lakshmi P Kunju, Fiona Maclean, Cristina Magi-Galluzzi, Jesse K McKenney, Rohit Mehra, Gabriella Nesi, Adeboye O Osunkoya, Maria M Picken, Priya Rao, Victor E Reuter, Paulo Guilherme de Oliveira Salles, Luciana Schultz, Satish K Tickoo, Scott A Tomlins, Kiril Trpkov, Mahul B Amin
Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA., Departments of Pathology and Urology, VCU School of Medicine, Richmond, VA., Department of Pathology, Houston Methodist Hospital, Weill Medical College of Cornell University., Department of Pathology, University of Chicago, Chicago., Institute of Pathology, Friedrich-Alexander-University, Erlangen, Germany., William Beaumont Hospital, Royal Oak., Johns Hopkins Hospital, Baltimore, MD., Memorial Sloan Kettering Cancer Center, New York, NY., Indiana University School of Medicine, Indianapolis, IN., Department of Pathology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy., Department of Pathology, Hôpital Tenon, Assistance Publique-Hôpitaux de Paris, UPMC Paris VI, Paris, France., Department of Pathology, AC Camargo Cancer Center, São Paulo., Cancer Diagnosis and Pathology Group, Kolling Institute of Medical Research Royal North Shore Hospital and University of Sydney., Charles University Hospital, Pilsen, Czech Republic., Brigham and Women's Hospital, Boston, MA., Institute of Pathology, Kantonsspital St Gallen, St Gallen, Switzerland., Department of Pathology and Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI., Douglass Hanly Moir Pathology, Sydney, NSW, Australia., Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, OH., Division of Pathological Anatomy, University of Florence, Florence, Italy., Emory University School of Medicine, Atlanta, GA., Department of Pathology, Loyola University, Maywood, IL., MD Anderson Cancer Center, Houston, TX., Anatomic Pathology, Mario Penna Institute, Hospital Luxemburgo, Belo Horizonte, Brazil., Institute of Anatomic Pathology, Piracicaba, Brazil., Calgary Laboratory Services, University of Calgary, Calgary, AB, Canada.