American Urological Association - Urothelial Papilloma


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Urothelial Papilloma

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  • 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.
  • 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.
  • Recurrence rate of 9-31%, but with no risk for progression to higher-grade tumors.

* For any urothelial tumor to be called "papillary" the papillae should have a central fibrovascular core.