Answer: C

Histological Description: Infiltrating the TUR specimens are cribriform glands, nests and cords of cells, some with necrosis. The same tumor is seen growing with some of the prostatic ducts. Tumor involves thick muscle bundles suggestive of bladder neck involvement. The tumor cells have amphophilic cytoplasm with enlarged nuclei and prominent nucleoli but are relatively uniform from cell to cell. Focally, there are areas of squamous differentiation with keratin pearl formation.

Discussion. The presence of cribriform glands on a TUR is almost pathognomic for prostatic adenocarcinoma. Bladder adenocarcinoma, either by itself or as a pattern of divergent differentiation in urothelial carcinoma, resembles gastrointestinal adenocarcinoma, where a cribriform pattern is not seen. This tumor was stained with prostate markers and was positive but also labeled in the squamous areas with gata-3 and p63. The presence of these markers, which are negative in usual prostate adenocarcinoma, can be seen in areas of squamous differentiation and does not exclude the diagnosis of prostatic adenocarcinoma. Adenosquamous carcinoma is rare and typically seen following prior hormonal therapy for advanced prostate cancer, but can also be seen de novo without prior therapy. Typically this is an aggressive disease with most patients dead within a year.