Editing Bladder Cancer: Pathology (section)

=== Histologic variants of urothelial cancer ===
* '''75% of urothelial carcinomas are classified as pure, while 25% have a secondary histological variant'''
* Squamous
** Most common (20-40%)
** Urothelial with squamous differentiation outcomes similar to pure urothelial
* Glandular
** Second most common (20%)
** Urothelial with glandular differentiation outcomes similar to pure urothelial
* '''<span style="color:#ff0000">Sarcomatoid</span>'''
** '''<span style="color:#ff0000">Aggressive</span>; consider upfront cystectomy'''
* '''<span style="color:#ff0000">Plasmacytoid</span>'''
** '''<span style="color:#ff0000">Aggressive; consider upfront cystectomy'''
*** '''Usually manifests at an advanced stage</span>'''
*** '''Respond very poorly''' '''to systemic chemotherapy'''
*** Median survival < 27 months from time of diagnosis
* '''<span style="color:#ff0000">Micropapillary</span>'''
** '''<span style="color:#ff0000">Aggressive</span>; consider upfront cystectomy'''
*** High (≈70%) progression rate from NMIBC to MIBC with a high subsequent metastatic rate despite treatment; usually manifests at an advanced stage
*** Cancer-specific survival <22% at 4 years despite aggressive chemotherapy and surgical resection in patients with locally advanced disease'''
** '''<span style="color:#ff0000">The most effective treatment for all stages of micropapillary urothelial carcinoma is surgical resection.</span>'''
*** '''Treatment with transurethral resection and BCG therapy is ineffective unless the tumor is completely resected'''
*** '''<span style="color:#ff0000">Neoadjuvant chemotherapy does not appear effective in micropapillary urothelial carcinoma, and may actually worsen survival by delaying therapy when compared with immediate cystectomy.</span>'''
* '''<span style="color:#ff0000">Nested</span>'''
** Rare
** Associated with higher stage and nodal invasion
** Oncological outcomes comparable to patients with pure urothelial carcinoma when matched by stage in both the NMIBC and MIBC setting
** '''Can be confused with benign lesions, such as Von Brunn nests that are in the lamina propria, cystitis cystica, and inverted papillomas'''
* '''<span style="color:#ff0000">Clear cell variant of urothelial carcinoma</span>'''
** '''<span style="color:#ff0000">Not associated with worse prognosis</span>'''
* '''Adenocarcinoma differentiation'''