Prostate Gland Anatomy

• The prostate is a funnel-shaped, inverted pyramid with a glandular structure surrounded by a capsule.
• The prostate is located in the retroperitoneum.
• It is the largest accessory gland in the male reproductive system.
• The prostate secretes a thin, milk-colored fluid, which is about 30% of the total seminal fluid volume.

Relational Anatomy

• The anterior of the prostate relates to the pubic bone and is separated by extraperitoneal fat.
• The posterior of the prostate relates to the rectum and is separated by rectovesical septum.
• The superior of the prostate relates to the urinary bladder, and the bladder base is continuous with the neck of the bladder.
• The inferior of the prostate relates to the urogenital diaphragm, with the apex of the prostate lies on the upper surface of urogenital diaphragm.
• The urethra exits the apex on the inferior-anterior surface.

Anatomy

• Seminal Vesicles are two sac-like outpouchings of the vas deferens and are located adjacent to the superior-posterior aspect of prostate, between the urinary bladder and rectum.
• Ejaculatory Ducts pass through the central zone and empty into the urethra, originating from the combination of the vas deferens and the seminal vesicle.
• The Verumontanum is a longitudinal ridge within the urethra, in which the orifices of the ejaculatory ducts are located about midpoint of prostatic urethra near the apex on either side.
• The inferior vesical artery primarily provides arterial blood to the prostate.
• The Uticle is glandular grouping at the crest of the verumontanum that appears on TRV images of prostate at the level of verumontanum.
• The Uticle is a remnant of the paramesonephric duct and urogenital sinus.
• The Eiffel Tower sign demonstrates, on TRV images of prostate at the level of verumontanum caused by shadowing of by the edge artifact or calcification of the prostatic urethra.

Organogenesis

• The mesonephric/wolffian ducts are responsible for male reproductive system development.
• The paramesonephric/Müllerian ducts form the female reproductive system.
• A portion of each mesonephric duct develops into the ejaculatory duct, vas deferens and seminal vesicle.
• By the 11th gestational week, the prostate forms the urogenital sinus.
• Prostate development begins as multiple solid outgrowths from the prostatic portion of the urethra, on the posterior side of the urogenital sinus.
• These outgrowths penetrate surrounding mesenchyme to form five prostatic lobes.
• Maturation continues, and the gland enters a quiescent state until puberty.

Prostate Anomalies

• Seminal Vesicle Agenesis is associated with Ipsilateral renal agenesis, Ipsilateral agenesis of vas deferens and Cystic fibrosis.
• Prostate Agenesis is associated with 5 a-reductase deficiency and testicular feminization.
• Congenital Seminal Vesicle Cysts is associated with Ipsilateral renal agenesis/dysplasia, Autosomal dominant polycystic kidney disease and Zinner Syndrome, resulting in a triad of unilateral renal agenesis, ipsilateral seminal vesicle obstruction and ejaculatory duct obstruction.

Prostate Zones

• Peripheral Zone is posterior and contains 70% of the prostatic glandular tissue.
• Cancer occurs most commonly in the peripheral zone, near the apex of prostate.
• Central Zone is superior and contains 25% of glandular tissue.
• The ejaculatory ducts pass through central zone to the urethra,
• The transitional zone is on the lateral sides of the proximal prostatic urethra and contains 5% of glandular tissue.
• The fibromuscular stroma is anterior and a non-glandular portion unaffected by cancer, prostatitis, or hyperplasia.
• The periurethral glandular zone is the tissue that lines the proximal prostatic urethra, making up less than 1% of cancer here since it runs along the smooth muscle wall.

Prostate Size

• The prostate gland measures around 4 cm width, 3 cm S-I and 2-3 cm AP.
• The normal volume of the gland is determiend by the formula: Volume = L x W x H x 0.52.
• The normal average weight of normal gland is 25g.

Sonographic Appearance

• Normal prostate symmetry and a smooth capsule without disruption visible.
• Homogeneous base and glandular tissue are isoechoic to the surroundings.
• Central gland is more hyperechoic than peripheral gland.
• Seminal vesicles are hypoechoic, multiseptated, and symmetric structures.
• Cancer appears varied appearance with either diffuse or focal lesions.
• The classic appearance of prostate cancer on US is a hypoechoic, peripherally-oriented lesion, but hypoechoic lesions are not always cancer.
• The presence of larger lesions with higher PSA levels increases the likelihood of cancer.

Prostate Specific Antigen (PSA)

• PSA is a single-chain glycoprotein.
• The upper limit of normal for PSA is 4ng/mL.
• Infection can cause elevated Levels, for which 4-6 weeks of antibiotics can be given and PSA can be re-checked.
• PSA velocity measures change in PSA level providing cancer risk information levels.
• PSA levels normally increase slowly with age.
• PSA density is the PSA level divided by the prostate volume with an increased likelihood of cancer with a higher PSA density.

Clinical Role of Prostatic Evaluation

• The advantages are high-resolution imaging, complementing digital rectal exam, no ionizing radiation, cost-effective compared to other imaging and dynamic imaging of blood flow.
• The application includes biopsy guidance and complementing digital rectal examination.
• Indications can differentiate from cystic versus solid palpable lesions, evaluation of abnormal prostate-specific antigen blood tests/inflammatory process, male infertility, guidance during biopsy or other/invasive procedures and evaluation of urination and/or ejaculation clinical symptoms.

Examination and Techniques

• Clinical complaints include hematospermia, Pain on ejaculation, Dysuria and Perineal pain.
• Transrectal Ultrasound (TRUS) is conducted with patient in LLD position, transducer placed in rectal cavity, close proximity to the target with improved resolution & visualization and empty bladder. A cleansing enema and prophylactic antibiotics are administered.
• With Transabdominal approach, a full urinary bladder is needed due to limited visualization and to use as an acoustic window since TRXDS has limited resolution.
• Transrectal/endorectal orientations of the prostate image are inverted on the sonography while imaging.

Transabdominal Technique

• The urinary bladder is used as an acoustic window.
• The transabdominal approach only diagnoses gross abnormalities.

Transrectal Technique

• Endorectal, end-fire transducers acquire transverse and sagittal images of the prostate.

Prostate Anomalies

• Seminal Vesicle Agenesis is associated with Ipsilateral renal agenesis, Ipsilateral agenesis of vas deferens and Cystic fibrosis.
• Prostate Agenesis is associated with 5 a-reductase deficiency and testicular feminization. Congenital Seminal Vesicle Cysts is associated with Ipsilateral renal agenesis/dysplasia, Autosomal dominant polycystic kidney disease and Zinner Syndrome, resulting in a triad of unilateral renal agenesis, ipsilateral seminal vesicle obstruction and ejaculatory duct obstruction.

Vascularity

• Capsular vessel sonograms show vessels in red that are demonstrated throughout the capsule.
• Periuretheral vessel sonograms are displayed by power Doppler.

Cysts of Male Pelvis

• Cysts can occur in male pelvis at the prostate, seminal vesicles, and vas deferens, presenting complex urinary retention or perineal pain.
• Müllerian duct cysts are tear-drop-shaped cysts located in the midline, extending above the prostate, posterior to the bladder, originating in verumontanum that DO NOT communicate.
• Urticle cysts are tear-drop-shaped cysts located at midline, associated with hypospadias, cryptorchidism, and renal agenesis that FREELY communicates with the prostatic urethra.
• Paramedican Cysts involving the Seminal Vesicle are located more lateral that Müllerian Duct cysts and are typically smaller.
• Paramedican Cysts involving Ejaculatory Ducts are located laterally, caused by congenital or acquired obstruction of ejaculatory ducts, causing hematospermia, ejaculatory pain, and infertility.

Benign Prostatic Hypertrophy (BPH)

• A common symptomatic, tumor-like condition of smooth muscle and epithelial cell proliferation in the transitional zone.
• The causes are in response to hormonal and inflammatory factors. Rare under the age of 30, seen in men over age 40, peak at age 60.
• Symptoms: Difficulty starting a stream, urinary frequency/ nocturia and Small urine stream.
• Soft, boggy, and nodular masses can be felt on the rectal exam.

Prostate Calcifications

• Endogenous calculi are within prostate and from for prostatic fluid, true prostatic stones and corpora amylacea.
• Exogenous calculi are found in urethra and primarily originate from urine.
• Sonographic appearance include clusters or if ejaculatory ducts or urethra is visualized in the sagittal plane to make visualization.
• Calculi are easily seen with sonography and can vary in size from very small to 3cm and/or greater.
• Calculus is often incidental findings and often show posterior shadowing.

Prostatitis

• Can be difficult to diagnose clinically and sonographically. Inflammation of prostate appears demonstrated by leukocytes in prostatic fluid.
• Four categories include acute bacterial, chronic bacterial, chronic pelvic pain (CPPP) and asymptomatic Inflammatory.
• Chronic pelvic pain is either inflammatory or non-inflammatory that causes varying levels of Leukocytes, EPS levels and Peneal pain.

Prostate Cancer

• Lifetime risk of prostate cancer in men is about 15% (1 in 6.67).
• Incidence increases with age and family history.
• It is the most common cancer and second-most deadly cancer in American men.
• Diagnosis typically occurs when the patient is over 65 years old.
• 80% of cancers originate in outer gland, typically the peripheral and central zone.
• 20% occur in the inner gland, typically the periurethral and transitional zones.
• The “beak” in the central zone can be seen whenever anatomical weakness is present.
• Surgical encapsulated defined plane present.

Cancer Classification (Grading)

• The Gleason Grading System evaluates prostate cancer prognosis based on microscopic appearance Cancers with higher scores are more aggressive.
• The predominant pattern is each given a grade between 1 and 5 and added together, as well as the second most common pattern.
• A high-grade prostate cancer appears with a Gleason score of 8, 9, or 10.
• Cancer Stage 1 is a Small lesion, low PSA and low Gleason.
• Cancer Stage 2 is a lesion in the prostate with medium PSA level.
• Cancer Stage 3 is a lesion outside of the prostate with high PSA level.
• Cancer Stage 4 is metastatic, spread to the lymph nodes, bone, and other organs.

Biopsy techniques

• Sonoghraphy provides visual for lesion direction.
• Systematic sextant and parasagital sextant are also options.

Concise summary of the prostate gland's structure and location within the male reproductive system. Covers relational anatomy, including connections to the pubic bone, rectum, urinary bladder, and urogenital diaphragm. Fluid secreted by the prostate accounts for 30% of seminal fluid volume.