Home Education AUAUniversity Education Products & Resources Pathology for Urologists Urinary Bladder Non-invasive Urothelial Neoplasms Inverted Papillary Neoplasms

Inverted Papillary Neoplasms

Image A

Image B

  • Papillary tumors may be associated with a variable degree of inverted growth into lamina propria, often as a concomitant component.
  • Uncommonly, growth of papillary tumor is purely endophytic (image A).
  • Because of inverted growth, may simulate invasive urothelial carcinoma.

Image C

Image D

  • Histology:
    • Round, smooth outline with no stromal reaction (image B), (image C), & (image D) (distinguish from invasive urothelial carcinoma nests which is irregular, has paradoxical or squamoid differentiation and stromal reaction).
    • Grading is similar to the exophytic papillary tumors (inverted PUNLMP, low-grade and high-grade urothelial carcinoma).
  • Prospective studies with uniform criteria or assessing clinical significance not yet performed.