vesical urothelial carcinoma

Definition: Urothelial carcinoma is the most common tumor of the urinary bladder, accounting for approximately 90% of tumors in this anatomical location.

Urothelial carcinoma has a propensity for divergent differentiation, with the most common variant being squamous and the next being glandular.

Variants

 nested variant
 inverted papilloma-like variant
 micropapillary variant
 microcystic variant
 lymphoepithelioma-like variant
 plasmacytoid/lymphoma-like variant
 clear cell (glycogen-rich) variant
 lipoid cell variant
 with syncytiotrophoblastic giant cells
 sarcomatoid urothelial carcinoma (carcinosarcoma)
 small cell carcinoma
 urothelial carcinoma with mixed differentiation
 squamous differentiation
 glandular differentiation
 large cell undifferentiated carcinoma
 unusual stromal reactions

• pseudosarcomatous stroma
• stromal osseous
• cartilaginous metaplasia
• steoclast-type giant cells
• prominent lymphoid infiltrate

Differential diagnosis

 benign lesions

• cystitis cystica
• cystitis glandularis
• inverted papilloma
• paraganglioma
• nephrogenic metaplasia

Benign features of Bladder Carcinoma

Carcinoma > Benign lesions they Mimic
1. nests > von Brunn nests
2. small tubules > nephrogenic adenoma
3. medium-sized glands > cystitis glandularis
4. cysts > cystitis cystica
5. inverted growth > inverted papilloma
6. low grade squamous cell > squamous metaplasia carcinoma
7. myxoid sarcomatoid carcinoma > inflammatory pseudotumor

8. plasmacytoid carcinoma > chronic inflammation

LOH

 15q13.2-q21.1 LOH

See also

 urothelial carcinomas

References

 Paner GP, Ro JY, Wojcik EM, Venkataraman G, Datta MW, Amin MB. Further characterization of the muscle layers and lamina propria of the urinary bladder by systematic histologic mapping: implications for pathologic staging of invasive urothelial carcinoma. Am J Surg Pathol. 2007 Sep;31(9):1420-9. PMID: #17721199

Reviews

 Lopez-Beltran A, Cheng L. Histologic variants of urothelial carcinoma: differential diagnosis and clinical implications. Hum Pathol. 2006 Nov;37(11):1371-88. PMID: 16949919

 Wu XR. Urothelial tumorigenesis: a tale of divergent pathways. Nat Rev Cancer. 2005 Sep;5(9):713-25. PMID: 16110317