[Histopathology of urothelial carcinomas: crucial for patient management].

Urothelial carcinomas include tumors with very different clinical outcomes: 70-80% of urothelial carcinomas are genetically stable and are associated with a favorable prognosis, but 20-30% are genetically unstable and have a high progression rate. Therefore, the current World Health Organization classification (2004) differentiates the histologic grade as low grade (LG) or high grade (HG). Unequivocal language is mandatory to optimize therapy and assess prognosis. In addition to TNM classification and histologic grade, genetic factors such as mutations of p53, fibroblast growth factor receptor 3 (FGFR3), and phosphatidylinositol-3-kinase (PIK(3)CA) are relevant in patients' prognoses.