ReviewsFrom the Upper to the Lower Urinary Tract—An Update on Classification, Grading, and Variants of Urothelial NeoplasiaUdager, Aaron Mark MD, PhD*; Smith, Steven Christopher MD, PhD†‡Author Information From the *Department of Pathology, University of Michigan Health System, Ann Arbor, MI; †Department of Pathology and ‡Division of Urology, Department of Surgery, VCU Health System, Richmond, VA. Reprints: Steven Christopher Smith, MD, PhD, Departments of Pathology and Urology, Virginia Commonwealth University Health System, PO Box 980662, 1200 E. Marshall St, Richmond, VA 23298. E-mail: firstname.lastname@example.org. The authors have no funding or conflicts to declare. AJSP: Reviews & Reports: 11/12 2016 - Volume 21 - Issue 6 - p 251-260 doi: 10.1097/PCR.0000000000000163 Buy Metrics Abstract Our classification for urothelial neoplasms has evolved substantially in the time since the 1973 World Health Organization (WHO) system, through the groundbreaking 1998 WHO/International Society of Urological Pathology consensus and beyond. Herein, timely in light of the newly released fourth edition 2016 WHO Classification of Tumours of the Urinary System and Male Genital Organs, we review the evolution and establishment of contemporary understanding, as well as entertain some emergent concepts, including urothelial neoplasia associated with bladder diverticula. Finally, in light of the remarkable morphologic plasticity of urothelial carcinoma, we review new findings pertaining to the variants of this disease, emphasizing variants that are recently described or that present diagnostic challenges. Taken together, the picture is that of a disease where, similar to emerging cytologic classifications and molecular adjunctive tests, our diagnostic approach continues to converge on designating categories of disease reflective of biologic potential and targeted for clinical management. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.