[Tumor-like and preneoplastic lesions as well as low risk and high risk urothelial tumors].

In its first part the review deals with all known hyperplastic, metaplastic as well as dysplastic urothelial changes and discusses their possible preneoplastic nature. The various changes are classified as indirect, facultative and obligatory premalignant lesions. In its second part, the review considers the tumor-like growths. In particular, it focuses on the pseudotumorous effects of various urocystitis types, postoperative spindle cell pseudosarcoma, glandular and nephrogenic metaplasias, malakoplakia and some tissue heterotopias and malformations. In its last part, the review critically compares the classification principle of the urothelial neoplasias into low-risk and high-risk tumors with other tumor classifications (superficial carcinoma/low-grade and high-grade tumors). The significance of recent study results for assessing the risk of urothelial carcinomas is discussed.