WHO/ISUP classification of the urothelial tumors of the urinary bladder
Background: The authors present the current classification of urothelial neoplasms of the urinary bladder. The classification of urothelial tumors of the urinary bladder of 1973 was despite some imperfection relatively successfuly used for more than thirty years. The three grade classification of papillary urothelial tumors without invasion has been based on evaluation of variations in architecture of covering epithelium and tumor cell anaplasia. As reccomended by the International Society of Urological Pathologists (ISUP), the World Health Organisation (WHO) accepted the new WHO/ ISUP classification in 1998 that was revised in 2002 and finally published in 2004. With intention to avoid unnecessary diagnosis of cancer in patients having papillary urothelial tumors with rare invasive or metastastatic growth, this classification introduced a new entity, the papillary urothelial neoplasia of low malignant potential (PUNLMP). The additional change in classification was the division of invasive urothelial neoplasms only to low and high grade urothelial carcinomas.
Conclusions: The authors’ opinion is that although the old classification is not recommended for use anymore the new one is not solving the elementary reproaches to previous classification such as terminological unsuitability and insufficient scientific reasoning. Our proposed solution in classification of papillary urothelial neoplasms would be the application of criteria analogous to that used in diagnostics of papillary noninvasive tumors of the head and neck or alimentary tract.
Mostofi FK, Sobin LH, Torloni H. Histological typing of urinary bladder tumors. Geneva: WHO; 1973.
Lopez-Beltran A, Montironi R. Non-invasive urothelial neoplasms: according to the most recent WHO classification. Eur Urol 2004; 6: 170–6.
Epstein JI, Amin MB, Reuter VR, Mostofi FK. The World Health Organization/International Society of Urological Pathology consensus classification of urothelial (transitional cell) neoplasms of the urinary bladder. Bladder Consensus Conference Committee. Am J Surg Pathol 1998; 22: 1435–48.
Reuter VR, Epstein JI, Amin MB, Mostofi FK, the Bladder Consensus Conference Committee. A newly illustrated synopsis of the World Health Organi
zation/ International Society of Urological Pathology (WHO/ISUP) consensus classification of urothelial (transitional-cell) neoplasms of the urinary bladder. J Urol Pathol 1999; 11: 1–28.
Eble JN, Sauter G, Epstein JI, Sesterhenn IA. Pathology and genetics of tumours of the urinary system and male genital organs. Lyon: IARC Press; 2004.
Bircan S, Candir O, Serel TA. Comparison of WHO 1973, WHO/ISUP 1998, WHO 1999 grade and combined scoring systems in evaluation of bladder carcinoma. Urol Int 2004; 73: 201–8.
Campbell PA, Conrad RJ, Campbell CM, Nicol DL, MacTaggart P. Papillary urothelial neoplasm of low malignant potential: reliability of diagnosis and outcome. BJU Int 2004; 93: 1228–31.
Cheng L, Bostwick DG. World Health Organization and International Society of Urological Pathology classification and two-number grading system of bladder tumors: reply. Cancer 2000; 88: 1513–6.
Cheng L, MacLennan GT, Zhang S, Wang M, Pan CX, Koch MO. Laser capture microdissection analysis reveals frequent allelic losses in papillary urothelial neoplasm of low malignant potential of the urinary bladder. Cancer 2004; 101: 183–8.
Yin H, Leong AS. Histologic grading of noninvasive papillary urothelial tumors: validation of the 1998 WHO/ISUP system by immunophenotyping and follow-up. Am J Clin Pathol 2004; 121: 679–87.
Mai KT, Elmontaser G, Perkins DG, Yazdi HM, Stinson WA, Thijssen A. Histopathological and immunohistochemical study of papillary urothelial neoplasms of low malignant potential and grade associated with extensive invasive low-grade urothelial carcinoma. BJU Int 2004; 94: 544–7.
Curry JL, Wojcik EM. The effects of the current World Health Organization/ International Society of Urologic Pathologists bladder neoplasm classification system on urine cytology results. Cancer 2002; 96: 140–5.
Ramos D, Ruiz A, Morell L, Navarro S, Villamon R, Gil-Salom M, LlombartBosch A. Prognostic value of morphometry in low grade papillary urothelial bladder neoplasms. Anal Quant Cytol Histol 2004; 26: 285–94.
Knowles MA. What we could do now: molecular pathology of bladder cancer. Mol Pathol 2001; 54: 215–21.
The Author transfers to the Publisher (Zdravniški vestnik/Slovenian Medical Journal) all economic copyrights following form Article 22 of the Slovene Copyright and Related Rights Act (ZASP), including the right of reproduction, the right of distribution, the rental right, the right of public performance, the right of public transmission, the right of public communication by means of phonograms and videograms, the right of public presentation, the right of broadcasting, the right of rebroadcasting, the right of secondary broadcasting, the right of communication to the public, the right of transformation, the right of audiovisual adaptation and all other rights of the author according to ZASP.
The aforementioned rights are transferred non-exclusively, for an unlimited number of editions, for the term of the statutory
The Author can make use of his work himself or transfer subjective rights to others only after 3 months from date of first publishing in the journal Zdravniški vestnik/Slovenian Medical Journal.
The Publisher (Zdravniški vestnik/Slovenian Medical Journal) has the right to transfer the rights, acquired parties without explicit consent of the Author.
The Author consents that the Article be published under the Creative Commons BY-NC 4.0 (attribution-non-commercial) or comparable licence.