Prostatic ductal adenocarcinoma is composed of tall columnar cells arranged in papillary, ductal, and cribriform structures. Many cases involve the large periurethral prostatic ducts. The tumor projects as an exophytic mass into the urethra near verumontanum. The tumors involving more peripheral prostatic ducts may be sampled on needle biopsies as shown here. With high molecular weight cytokeratin immunostain, it shows complete lack of basal cells (as seen in this image). The benign glands on the upper left with prominent basal cell layer serve as a nice internal positive control.