A Clinically Relevant Approach to Imaging Prostate Cancer: Review

Abstract

The zonal anatomy of the prostate is likened to a cone containing a scoop of ice cream [5, 6]. The cone is the peripheral zone and makes up 70% of the prostate gland by volume in young men. The ducts of the peripheral zone glands drain to the distal prostatic urethra. The scoop of ice cream is the central zone and makes up 25% of the prostate gland volume in young men. The ejaculatory ducts traverse the central zone, and the ducts of the central zone drain to the region of the verumontanum clustered around the entry of the ejaculatory ducts. The remaining 5% of the prostate consists of the transition zone, which is composed of two small bulges of tissue that surround the anterior and lateral parts of the proximal urethra in a horseshoelike fashion (Fig. 1). This two-compartment model is deficient anteriorly where the peripheral zone is interrupted by the anterior fibromuscular stroma, a band of smooth muscle mixed with fibrous tissue that forms a thick shield over the anterior aspect of the gland. As a result, the peripheral zone lies predominantly lateral and posterior to the central zone. The prostate zones are defined histologically and therefore many prostatic diseases have a zonal distribution. Seventy percent of adenocarcinomas arise in the peripheral zone and 20% of adenocarcinomas arise in the transition zone, while only 10% of adenocarcinomas arise in the central zone. Prostate adenocarcinomas arise in the glandular components of the prostate [5].