• Nadira Mamoon
  • Muhammad Ashraf Iqbal
  • Shahid Jamal
  • Muhammad Luqman


Background: Classification of urothelial bladder tumours is an important factor in the treatmentand prognosis of these lesions. Over the years many classifications have been proposed for thispurpose. The objective of this study was to classify urothelial neoplasms of the urinary bladderusing the latest WHO/ ISUP Consensus Classification 1998 and WHO Classification 1972 andcompare the two regarding interobserver variability. Methods: This study included 100consecutive biopsy specimens of urothelial neoplasms of the urinary bladder diagnosed at thedepartment of Histopathology, Armed Forces Institute of Pathology, Rawalpindi. These wereclassified according to WHO Classification 1972 and WHO/ISUP Consensus Classification 1998by 2 groups of pathologists independently. The tumour categories for WHO classification 1972;papilloma, and transitional cell carcinoma (TCC) grades I, II and III were compared with theWHO/ISUP Consensus Classification entities of papilloma, papillary neoplasm of low malignantpotential, low grade and high grade papillary carcinomas. Kappa statistics were used to evaluateinterobserver variability. Chi square test was used to calculate significance. Results: There wasagreement on 80 tumours between the two groups of histopathologists when using WHOclassification 1972 while there was agreement on 95 tumours using WHO/ISUP consensusclassification. The value of Kappa for WHO Classification was 0.68 (good agreement) whereas forWHO/ISUP Consensus Classification it was 0.91 (excellent agreement). The difference betweenthe two systems was statistically significant (p<0.001). Kappa values were less for benign andborderline lesions using both systems. Conclusions: WHO/ISUP Consensus Classification 1998showed less interobserver variability than WHO Classification 1972 in the evaluation of bladdertumours . It was found easier to apply by both groups. There was less agreement on the benign andborderline lesions using both the classifications.Key Words: Transitional cell carcinoma, Urinary bladder neoplasms, Urothelial neoplasia.


Parkin DM, Pisani P, Ferlay J .Estimates of the worldwide

incidence of eighteen major cancers in 1985. Int J Cancer


Wingo PA, Tong T, Bolden S. Cancer statistics 1995. Cancer

J Clin 1995; 45(1): 8-11.

Cheng L, John C, Cheville JC, Neumann RM, Bostwick DG.

Natural history of urothelial dysplasia of the bladder. Am J

Surg Pathol 1999; 23(4): 443-7.

Willet F, Whintmore JR. Summary of all phases of bladder

carcinoma. J Urol 1978; 5: 335-8.

Cotran RS, Kumar V, Collins T. Robbins Pathologic Basis of

Disease. 6th ed. Philadelphia: Saunders, 1999: 1003-04.

Broders AC. Epithelioma of the genitourinary organs. Ann

Surg 1922; 75: 574-604.

Dean AL, Ash JE. Study of bladder tumours in the registry of

the American Urological Association. J Urol 1950;


Mostofi FK, Sobin LH, Torloni H. Histological typing of

urinary bladder tumours. International Classification of

tumour (no.10) Geneva, World Health Organization, 1973.

Epstein JI, Amin MB, Reuter VR, Mostofi FK. The World

Health Organization/ International Society of Urological

J Ayub Med Coll Abbottabad 2006;18(2)

Pathology Consensus Classification for urothelial

(transitional cell) neoplasms of the urinary bladder. Am J

Surg Pathol 1998; 22:1435-8.

Eble JN, Sauter G, Epstein JI, Sesterhenn IA. World Health

Organization Classification of Tumours Pathology and

Genetics of Tumours of The Urinary system and Male

Genital Organs. WHO Geneva (2004).

Cohen JA. A coefficient of agreement for nominal scales.

Educational Psychological Measurements 1960;20 (1):37-47.

Fleiss JL. Statistical methods for rates and proportions. 2nd

ed, New York: John Wiley, 1981: 135-7

Landis JR, Koch GG. The measurement observer agreement

for categorical data. Biometrics 1977; 33: 159-74.

Murphy WM, Grignon DJ ,Perlman EJ (eds) Tumours of

kidney , bladder and related urinary structures . AFIP Atlas

of Tumour Pathology. Fourth Series Fascicle Washington DC

,241- 361

Ooms ECM, Anderson WAD, Alons CL, Boon ME,

Veldhuizen RW. Analysis of the performance of pathologists

in the grading of bladder tumours. Hum Pathol 1983; 14:140-

Tosoni I, Wagner U, Sauter G, Egi G, Knonagel H, Alund G,

et al. Clinical significance of interobserver differences in the

staging and grading of superficial bladder cancer. BJU

International 2000;85:48-53.

Busch C, Engberg A, Norlen BJ, Stenkvist B. Malignancy

grading of epithelial bladder tumours. Reproducibility of

grading and comparison between forceps biopsy, aspiration

biopsy and exfoliative cytology. Scand J Urol Nephrol 1977;

: 43-8.

Schapers RF, Pauwels RP, Wijnen JT, Arends JW,

Thunnissen FB, Coebergh JW, et al. A simplified grading

method of transitional cell carcinoma of the urinary bladder:

reproducibility, clinical significance and comparison with

other prognostic parameters. Br J Urol 1994;73(6):625-31.

Yorukoglu K, Tuna B, Dikicioglu E, Duzcan E, Isisag A, Sen

S et al. Reproducibility of the 1998 World Health

Organization / International Society of Urologic Pathology

classification of papillary urothelial neoplasms of the

urinary bladder. Virchows Arch 2000;443 (6) :734-40

Epstein JL. The new World Health Organization /

International Society of Urologic Pathology (WHO/ISUP)

classification for TA, T1 bladder tumours: is it an

improvement? Crit Rev Oncol Hematol 2003;47(2):83-9.

Mikuz G. The reliability and reproducibility of the different

classifications of bladder cancer. In: Hauptmann S. Dietel M

. Sobinho-Simoes M eds. Surg Pathology update 2001. 18th

European Congress of Pathology. Berlin: ABW

Wissenschaftsverlag 2001: 114-5.

Busch C, Algab F. The WHO /ISUP 1998 and 1999 systems

for malignancy grading of bladder cancer. Scientific

Foundation and translation to one another and previous

systems. Virchows Arch 2002;441(2); 105-8.

Helpap B. New WHO classification of urothelial carcinoma

of the urinary bladder. Verh Dtsch Ges Pathol 2002;86;57-6

Most read articles by the same author(s)