Urothelial dysplasia and other flat lesions of the urinary bladder: clinicopathologic and molecular features

Hodges, Kurt B.; Lopez-Beltran, Antonio; Davidson, Darrell D.; Montironi, Rodolfo; Cheng, Liang

doi:10.1016/j.humpath.2009.07.002

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Volume 41, Issue 2 , Pages 155-162, February 2010

Urothelial dysplasia and other flat lesions of the urinary bladder: clinicopathologic and molecular features

Kurt B. Hodges, MD, MBA
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
Antonio Lopez-Beltran, MD, PhD
- Department of Pathology, Cordoba University, E-14004 Cordoba, Spain
Darrell D. Davidson, MD, PhD
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
Rodolfo Montironi, MD
- Institute of Pathological Anatomy and Histopathology, Polytechnic University of the Marche Region (Ancona), United Hospitals, 60020 Ancona, Italy
Liang Cheng, MD
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Urology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Corresponding author. Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.

Received 28 May 2009; received in revised form 2 July 2009; accepted 9 July 2009. published online 17 September 2009.

Summary

The 2004 World Health Organization classification system for urothelial neoplasia classifies flat-related preneoplastic lesions as urothelial hyperplasia (flat and papillary), reactive urothelial atypia, urothelial atypia of unknown significance, urothelial dysplasia (low-grade intraurothelial neoplasia), and urothelial carcinoma in situ (high-grade intraurothelial neoplasia). Each lesion is defined with precise nomenclature and strict morphologic criteria. In many cases, morphologic features alone suffice for diagnosis. Other cases may require a panel of immunohistochemical antibodies consisting of cytokeratin 20, p53, and CD44 for diagnosis. Recent molecular studies have provided further insight into the premalignant potential of these urothelial lesions. Herein, we present a review of flat urothelial lesions of the urinary bladder as defined by the 2004 World Health Organization classification with focus on the clinicopathologic, immunohistochemical, and molecular features.

Keywords: Bladder, Flat lesions, Urothelial dysplasia, Atypia of unknown significance, Papillary hyperplasia, Molecular pathogenesis