Prostatic adenocarcinoma identified on transurethral resection of bladder tumor: A clinicopathologic series of a diagnostically relevant potential pitfall.

Over the past 2 decades, we have increasingly encountered prostatic adenocarcinoma (PCA) presenting as urinary bladder tumors in routine practice as well as among consultation/medicolegal cases. Given the ramifications of a potential misdiagnosis of PCA as urothelial carcinoma (UC), herein we explore clinicopathologic features among a large cohort of PCA identified on transurethral bladder tumor resection (TURBT). A retrospective re-review identified 54 TURBTs containing PCA from a single tertiary care academic hospital (2003-2025). Of the 27 patients with prior PCA history, urologists were concerned for PCA in 86 %, but history/suspicion was only conveyed in 32 % of accompanying specimen requisition sheets. For patients without PCA history, urologists were occasionally (29 %) suspicious for PCA, mentioning this possibility on requisition sheets in all (100 %) of cases. Most tumors were from the bladder neck or base (72 %). Pseudopapillary/papillary-like growth pattern was often seen (46 %). The predominant architecture was solid or nested/corded (70 %) followed by glandular (26 %) and acinar (4 %). Nuclei in most cases were uniform/round (89 %) with prominent nucleoli predominant in most cases (56 %) while the cytoplasm was more often "pale/bubbly" (72 %) versus "dense/glassy" (28 %). Pseudopapillary/papillary-like growth compounded with solid to nested architecture within PCA can mimic UC on TURBT specimens, although nuclear features/prominent nucleoli can be a helpful clue. While clinical/cystoscopic findings (e.g. tumor site) may suggest PCA on TURBT, this information does not always accompany the specimen, requiring confirmatory chart review for putative cases as well as judicious use of immunohistochemistry.