Growth and modeling of urothelial papillary tumors

The development of urothelial papillary tumors (UPT) has been interpreted from some histologic patterns to suggest that intraurothelial vascularization and opening of urothelial nests that have grown in the lamina propria are basic processes for the development, growth, and modeling of UPT. These basic processes can combine in different ways to form the complex structures that compose UPT.