[The nucleolus organizer region (Ag NORS) in urothelial tumors. Apropos of 10 cases].

The authors study nucleolar organisers (Ag NORS) in ten cases of urothelial tumours, graded as grade I in five cases, grade II in two cases, grade III in two cases and intermediate grade II-III in one case. Study of the NOR index showed a mean value of 3.89 for grade I, 4.66 for grade II, 5.88 for grade III and 4.90 for the intermediate grade II-III. Different values were recorded in the same heterogeneous tumours containing tumour zones of different grades, providing an additional argument in favour of the heterogeneity of these urothelial tumours and accounting for the difficulties of their classification reported in the literature. Adequate sampling should allow a more objective and more representative study of all of the tumours examined.