Study Type - Prognosis (case series) Level of Evidence 4 Objective To report the clinicopathological characteristics of 23 cases of ductal adenocarcinoma of the prostate (DCP) and discuss the implications for clinical management, as DCP is considered an aggressive subtype of prostate adenocarcinoma (PA). Patients and Methods The presence of DCP in transrectal ultrasonography-guided prostate biopsy (TRUSB) is associated with adverse pathological findings at radical prostatectomy (RP) and clinical outcomes, and the significance of detecting DCP initially in transurethral biopsy (UB) or transurethral resection (TURP) in the present era of screening with prostate-specific antigen (PSA) is unclear. The study included 23 cases of pure DCP without acinar PA diagnosed on UB or TURP. Demographic information, serum PSA level, follow-up surgical procedures (RP, TURP or TRUSB) and outcome data were collected. Results The mean age of the men was 67.5 years and the mean PSA level before the procedure was 12.5 ng/mL; 14 cases were detected on UB and nine were diagnosed on TURP. The mean (range) follow-up was 4 (1-23) months after the initial procedure. In all, 21 (89%) patients had DCP or PA in follow-up procedures. Two (11%) patients had no residual cancer, one on RP and the other on two repeat TURPs. DCP or PA was found in 12 RP cases; four patients had Gleason score 7 PA, three of which were organ-confined, and eight had Gleason score ≥8 PA. Extraprostatic extension, seminal vesicle invasion and regional lymph node metastasis were present in seven, six and two cases, respectively. ConclusionS Most DCP diagnosed on UB or TURP in this contemporary series was associated with aggressive PA, but a subset presented as a small periurethral tumour with no concomitant acinar PA, and was eradicated by the initial biopsy/TURP alone. We recommend that patients with a diagnosis of DCP on UB or TURP undergo follow-up TURP and TRUSB before radical surgery is offered. © 2009 BJU INTERNATIONAL.