Peritoneal invasion of prostate cancer directly confirmed during robot-assisted radical prostatectomy.

We encountered a case showing direct peritoneal invasion of prostate cancer during robot-assisted radical prostatectomy. If invasion of the seminal vesicle is suspected, the vesicorectal fossa should be examined during robot-assisted radical prostatectomy. Preoperative confirmation by diffusion magnetic resonance imaging of the peritoneum is also useful.