Histogenetically, bladder tumors are divided into two main categories, namely tumors of epithelial origin and tumors of non-epithelial, i.e. mesenchymal, tissue. According to statistics, 97% of bladder tumors originate from epithelial tissues.
Bladder tumors originating from epithelial tissues are divided into two categories: benign and malignant. Benign tumors include uroepithelial hyperplasia and atypical hyperplasia, papillomas, polyps, and adenomas. Malignant tumors include uroepithelial cell carcinoma, squamous cell carcinoma, glandular cell carcinoma, small cell carcinoma, and metastatic carcinoma. Uroepithelial carcinoma of the bladder is the most common, accounting for more than 90% of bladder tumors. Squamous cell carcinoma of the bladder is relatively rare, accounting for 3% to 7% of bladder tumors. Adenocarcinoma of the bladder is much less common and accounts for