[Diagnosis of adenocarcinoma in transurethral resection of the prostate: how much sampling is adequate]

The amount of prostatic tissue necessary to detect carcinoma in transurethral resection specimens with reasonable accuracy, was evaluated. The samples were taken from the patients with a clinical diagnosis of benign prostatic hypertrophy. Prostate chips from 647 such patients were examined microscopically. An average of 2.5 g of sample was mounted in each block. Adenocarcinoma was diagnosed in 58 cases (9.0%). Among them, 40 cases were in stage A1, and 18 in stage A2. Incidental carcinoma was found more frequently in prostate chips weighing less than 20 g. To detect carcinoma with 95% probability, at least 2 slides should be examined in stage A2, and 6 slides in stage A1.