Prostate Diseases

The prostate gland is a hormone-regulated organ made of muscle and gland tissue, found only in biological males. It sits where the urinary and reproductive tracts meet, which is why prostate problems often affect urination. The prostate is deep in the pelvis, just below the bladder neck and above the urogenital diaphragm, which holds the external urinary sphincter.

The prostate is shaped like an upside-down cone or a chestnut. Its base connects to the bladder neck, and its tip rests on the pelvic floor muscles. The gland is wrapped in a fibrous capsule, with another layer of pelvic fascia outside it. Between these layers is a network of veins called Santorini’s plexus, which is important during surgery. Behind the prostate, a layer called Denonvilliers’ fascia separates it from the rectum. This barrier helps prevent prostate cancer from spreading to the rectum and allows doctors to feel the back of the prostate during a Digital Rectal Examination (DRE).

The prostate starts to form between the 10th and 12th week of pregnancy. It develops from small buds in the urogenital sinus, influenced by fetal androgens. These buds grow into the surrounding tissue, which becomes the muscle and support structure of the gland. This early interaction is important for both normal development and for conditions like benign prostatic hyperplasia (BPH) later in life, which may reactivate these early growth pathways.

The prostatic urethra runs straight through the center of the prostate, bending slightly at the verumontanum, where the ejaculatory ducts enter. Because of this, when the prostate grows in the center, it can press on the urinary passage. Urinary control depends on two sphincters: the internal one at the bladder neck, which works automatically, and the external one at the tip of the prostate, which you control voluntarily. Prostate surgery can affect the internal sphincter, so protecting the external sphincter is key to keeping continence after surgery.

The Neurovascular Bundles Running along the posterolateral aspect of the prostate capsule (at the 5 o’clock and 7 o’clock positions) are the cavernous nerves, collectively termed the neurovascular bundles. These microscopic parasympathetic fibers originate from the pelvic plexus and are responsible for inducing penile erection. Their intimate proximity to the prostate capsule makes them highly vulnerable during radical prostatectomy. Understanding this anatomy is fundamental to the concept of “Nerve-Sparing” surgery, a technique refined at Liv Hospital to preserve sexual potency.

The prostate is made up of different zones, not just one type of tissue. In 1968, John McNeal introduced the idea of zonal anatomy for the prostate. Each zone develops differently, has its own tissue structure, and is prone to certain diseases.

• The Peripheral Zone makes up about 70% of the prostate in healthy young men. It wraps around the end of the urethra and extends to the back and sides. Most prostate cancers (70-80%) start in this zone. Since it forms the back of the prostate, tumors here can be felt during a rectal exam and are easy to reach for a biopsy.
• The Transition Zone (TZ): Originally constituting only 5% to 10% of the glandular tissue, this zone consists of two bilateral lobes surrounding the proximal urethra. The Transition Zone is the exclusive site of origin for Benign Prostatic Hyperplasia (BPH). As men age, hyperplastic nodules originating here expand exponentially, compressing the Peripheral Zone outward into a thin, fibrous shell known as the “surgical capsule.”
• The Central Zone makes up about 25% of the prostate and is shaped like a cone around the ejaculatory ducts, which pass through the prostate to the urethra. This zone comes from the Wolffian ducts during development. Cancers in this area are rare (1-5%) but are usually more aggressive when they happen.

The Anterior Fibromuscular Stroma is a layer of dense muscle and fibrous tissue that covers the front of the prostate. It does not have gland cells, so cancers rarely start here. However, large tumors from the Transition Zone can grow into this area, which makes them hard to detect during a rectal exam.