Invasion of Denonvilliers' fascia in radical prostatectomy specimens.

Denonvilliers' fascia consists of a single fibromuscular structure covering the posterior aspect of the prostate and surrounding the seminal vesicles. This structure has multiple layers that are fused together, and to the stroma of the prostate and seminal vesicles. A separate posterior layer of Denonvilliers' fascia was not seen during radical prostatectomy. The cleavable interprostatorectal plane extends posteriorly throughout the thickness of Denonvilliers' fascia and anteriorly to the muscular wall of the rectum. Medially this fascia is fused with the prostatic capsule into a single sheath and contains thick smooth muscle bundles in continuity with the prostatic stroma. In a series of 243 radical prostatectomy specimens for prostate cancer, we studied the morphological relationship of Denonvilliers' fascia with the prostatic capsule and stroma, and traced the progression of prostatic cancer in relation to the anatomical landmarks. In 19% of the cases tumor was found progressing within Denonvilliers' fascia, in the medial posterior area of the prostate, unrelated to perineural space invasion. For specimens with an intracapsular cancer volume of less than 12 cc, which may be cured by radical prostatectomy alone, the frequency of invasion of Denonvilliers' fascia was 13%. In these cases cephalad progression of cancer was seen almost exclusively in Denonvilliers' fascia overlying the central zone at the prostate base and surrounding the seminal vesicles. Invasion of Denonvilliers' fascia can lead to positive surgical margins if complete excision of this fascia is not performed during radical prostatectomy. Even among large tumors in our series there were no cases of tumor invasion completely through the full thickness of Denonvilliers' fascia at the posterior medial area and, therefore, rectal wall invasion was never suspected at this level.