The 1973 WHO classification of bladder tumours anticipated a probable need for eventual revision of the criteria for diagnosing papillary and flat bladder neoplasia. A workshop sponsored by the WHO consisting of pathologists, urologists, cytologists, oncologists and basic scientists interested in bladder tumours addressed this subject, and after a follow- -up meeting sponsored by the International Society of Urological Pathology, the classification and terminology used in this text were agreed upon. A major change is in the introduction of a new category: papillary urothelial neoplasm of low malignant potential. Many of the tumours previously designated as papillary transitional cell carcinoma, grade I now fall into that category. Another major change is in the designation of flat lesions, and this includes a definition of carcinoma in situ. Furthermore, a number of variant forms of urothelials carcinomas are included as well as new entities not recognized when the 1st edition was issued.

Histological Classification of Urinary Bladder Tumours

Definitions and Explanatory Notes
Epithelial Tumours of the Bladder
Non-epithelial Tumours
Miscellaneous Tumours
Metastatic Tumours and Secondary Extensions
Unclassified Tumours
Epithelial Abnormalities
Tumour-like Lesions
TNM Classification of Tumours of the Urinary Bladder
Illustrations.