Mimickers of Urothelial Carcinoma and the Approach to Differential Diagnosis

A broad spectrum of lesions, including hyperplastic, metaplastic, inflammatory, infectious, and reactive, may mimic cancer all along the urinary tract. This narrative collects most them from a clinical pathologic perspective, offering urologists general pathologists their salient definitory features. Together with classical, well-known, entities such as urothelial papillomas (conventional (UP) inverted (IUP)), nephrogenic adenoma (NA), polypoid cystitis (PC), fibroepithelial polyp (FP), prostatic-type (PP), verumontanum cyst (VC), xanthogranulomatous inflammation (XI), reactive changes secondary to BCG instillations (BCGitis), schistosomiasis (SC), keratinizing desquamative squamous metaplasia (KSM), post-radiation (PRC), vaginal-type (VM), endocervicosis (EC)/endometriosis (EM) (müllerianosis), malakoplakia (MK), florid von Brunn nest proliferation (VB), cystitis/ureteritis cystica (CC), glandularis (CG), among others, still other cellular proliferations concerning histological features poorly understood etiopathogenesis like IgG4-related disease (IGG4), PEComa (PEC), pseudosarcomatous myofibroblastic (post-operative spindle cell nodule (POS), inflammatory tumor (IMT)), are reviewed. Some these diagnoses problematic for urologists, pathologists, others both. Interestingly, right identification will allow correct diagnoses, thus, avoiding overtreatment. The literature selected this review also focuses on immunohistochemical and/or molecular data useful delineate prognosis.