Prostate

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The prostate is an accessory organ of the male reproductive system. It is a large and dense exocrine gland which is responsible for secreting a white alkaline fluid that makes up about 30 to 50% of the total seminal fluid volume (semen).

The prostate consists of approximately 70% glandular tissue and 30% fibromuscular stroma, and based on this composition, it can be divided into two parts: a fibromuscular part and a glandular part. 

The fibromuscular stroma (fibromuscular part) surrounds the anterior surface of the prostate and is composed of dense irregular connective tissue with a mix of smooth muscle fibers and elastic fibers. 

Its glandular part consists of four zones: central, peripheral, transitional and periurethral.

• The central zone is a cone-shaped region, with the wider portion at the base of the prostate and the apex surrounding the ejaculatory ducts. It contains approximately 25% of the overall glandular tissue.
• The peripheral zone envelops the central zone and the posterior as well as lateral portions of the prostate and is the site of origin of most prostate cancers. It contains approximately 70% of the overall glandular tissue.
• The transitional zone is located near the prostatic urethra. It is not very prominent in most young men. In older men, the transitional zone is enlarged considerably by benign prostatic hyperplasia, an extremely common benign proliferation of parenchymal cells. This zone comprises approximately 5% of the overall glandular tissue and houses the mucosal glands.
• The periurethral zone lies in proximity to the transitional zone and surrounds the prostatic urethra. It houses mucosal and submucosal glands.

Prostatic glands vary widely in size and have lumens that are lined by connective tissue folds. The connective tissue foldings result in the acini appearing highly irregular. Generally, they are lined by simple columnar or pseudostratified epithelium.

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