Inverted urothelial papilloma
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Inverted urothelial papilloma, also inverted papilloma, is a benign urothelial lesion that may be confused with urothelial carcinoma.
| Inverted urothelial papilloma | |
|---|---|
| Diagnosis in short | |
 Inverted urothelial papilloma. H&E stain. | |
|
| |
| LM | like papillomas... but grow downward; never have an exophytic component; nests have peripheral palisading of nuclei - important |
| LM DDx | low grade papillary urothelial carcinoma with an inverted growth pattern |
| IHC | Ki-67 -ve, CK20 -ve, p53 -ve (rarely +ve) |
| Site | urothelium - usu. urinary bladder |
|
| |
| Prevalence | uncommon |
| Prognosis | benign |
General
- May be confused with papillary urothelial carcinoma with an inverted growth pattern.
Microscopic
Features:
- Like papillomas... but grow downward.[1]
- According to THvdK,[2] inverted papillomas never have an exophytic component; if an exophytic component is present it is urothelial carcinoma. This is disputed by one paper from Mexico that examines two cases.[3]
- Nests have peripheral palisading of nuclei - important.
DDx:
- Low grade papillary urothelial carcinoma with an inverted growth pattern.
- Cystitis cystica.
Images
Case 1
Inverted papilloma - high mag. (WC/Nephron)
Inverted papilloma - intermed. mag. (WC/Nephron)
Case 2
IUP. (WC/KGH)
IUP. (WC/KGH)
IUP. (WC/KGH)
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IHC
May be useful versus inverted growth pattern UCC:[4]
- Ki-67 -ve.
- CK20 -ve.
- p53 -ve (rarely +ve).
See also
References
- ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 310. ISBN 978-0781765275.
- ↑ THvdK. 21 June 2010.
- ↑ Albores-Saavedra J, Chable-Montero F, Hernández-Rodríguez OX, Montante-Montes de Oca D, Angeles-Angeles A (June 2009). "Inverted urothelial papilloma of the urinary bladder with focal papillary pattern: a previously undescribed feature". Ann Diagn Pathol 13 (3): 158–61. doi:10.1016/j.anndiagpath.2009.02.009. PMID 19433293.
- ↑ Jones, TD.; Zhang, S.; Lopez-Beltran, A.; Eble, JN.; Sung, MT.; MacLennan, GT.; Montironi, R.; Tan, PH. et al. (Dec 2007). "Urothelial carcinoma with an inverted growth pattern can be distinguished from inverted papilloma by fluorescence in situ hybridization, immunohistochemistry, and morphologic analysis.". Am J Surg Pathol 31 (12): 1861-7. doi:10.1097/PAS.0b013e318060cb9d. PMID 18043040.