1. Benign Tumors of the Bladder
Epithelial Metaplasia
Leukoplakia
Inverted Papilloma
Papilloma
Nephrogenic Adenoma
Cystitis Cystica and Glandularis
Leiomyoma

2. Papilloma

3. Papilloma •Uncommon, comprises ~1% of papillary urothelial neoplasms.
•Patients are typically <50 years old and can be seen in children.
•Often encountered as de novo lesion (without prior urothelial neoplasm).
•Cystoscopy shows a small unifocal papillary or elevated lesion.
•Recurrence rate of 9-31%, but with no risk for progression to higher-grade tumors.

4. Papilloma •Histology:
◦Papillae (with fibrovascular core*) lined by normal-appearing urothelium, including presence of umbrella cells (image A) & (image B).
◦Nuclei elongated or oval.
◦Papillae are slender with minimal branching.
* For any urothelial tumor to be called "papillary" the papillae should have a central fibrovascular core.

5. Papilloma

6. Papilloma
Benign proliferative growth in the bladder that is composed of delicate stalks lined by normal-appearing urothelium. Papillomas had previously been categorized as grade 1 Ta tumors of the bladder until the World Health Organization (WHO) changed the classification of noninvasive bladder cancer in 1998.
Papillomas rarely have mitotic figures and lack markers of aggressive growth such as TP53 or RB mutations, but 75% of these tumors will have mutations in the fibroblast growth factor receptor-3 (FGFR-3).
Papillomas may recur, but they do not progress or invade.