Chapter 14 prostate gland

Embryogenesis

Paired mesonephric (Wolffian) ducts responsible for development of male reproductive system

•Portion of each form ejaculatory duct, vas deferens, and seminal vesicle

•11th week – prostate begins to form from urogenital sinus

•Continues to grow while testosterone is high during fetal development

 

 

Anatomy

Funnel-shaped, glandular structure

•Surrounded by fibrous capsule

•Measures approximately 4 x 3 x 2 cm

•Surrounds the proximal male urethra

•Base of prostate -  cephalic portion

•Apex – caudal portion

Vascular

•Supplied by internal iliac arteries and prostatic artery 

•Venous drainage is from veins of vas deferens, leading to internal iliac veins

 

Peripheral zone

•Comprises 70% of the glandular tissue

•Most common site of carcinoma

Peripheral zone location

Located posterior and lateral

Peripheral zone sonography

– homogeneous, isoechoic and separated from central zone by a hyperechoic band called the surgical band

Central zone

•Located at the base of the prostate

•Embedded in the funnel-shaped peripheral zone

•Narrows to the apex

•Echogenicity is greater than the peripheral zone

 

Transition zone

•Consists of two small lobules 

•Site of involvement by benign prostatic hyperplasia (BPH)

•Sonographically – becomes more hyperechoic and visible with BPH

Periurethral zone

•Embedded in smooth  muscle wall of the urethra

Utricle cyst

•Associated with genital anomalies – hypospadias, undescended testicles, renal anomalies

•Located midline

Associated with genital anomalies – hypospadias, undescended testicles, renal anomalies

Utricle cyst

•Located midline

Mullerian duct cyst

•Not associated with genital anomalies

•Unilateral renal agenesis may occur

•Found between bladder and rectum

•Sonographically – 

•Lateral from midline and superior to prostate base

•Anechoic, may have debris or calcifications

Mullerian duct cyst-Clinical findings

– partial urinary obstruction, hematospermia, infertility, rectal discomfort

Clinical findings-Sonographically

•Lateral from midline and superior to prostate base

BPH

Most common symptomatic tumor-like condition in male population over the age of 40

•Nodular formation in the transition zone

•Transurethral resection of the prostate (TURP) is performed to relieve symptoms

 

Patients present BPH with urinary symptoms 

•Urinary frequency, nocturia, difficulty

•Transurethral resection of the prostate (TURP) is performed to relieve symptoms

Three primary types BPH

•Homogenous stromal hyperplasia - hypoechoic

•Glandular hyperplasia – hypoechoic or hyperechoic

•Combination of stromal and glandular – most common and appears heterogeneous

Calcification

Common but rarely cause symptoms

•Classified into two groups

Endogenous

found within substance of the prostate and form from prostatic fluid (true prostatic stones)

Exogenous

found in urethra and derived from urine

Sonographically calcification

Easily seen

•Lie in parenchyma of the gland

•Size can vary

•Distal acoustic shadowing

Protatitis

Difficult to diagnose clinically and sonographically

•Caused by ascent of bacteria from lower urethra to prostatic urethra

For type of protatitis

•Acute bacterial prostatitis

•Chronic bacterial prostatitis

•Chronic pelvic pain syndrome

•Asymptomatic inflammatory prostatitis

Sonography of prostatitis

•Hypoechoic halo in periurethral area

•Heterogeneous peripheral gland

•Hyperemic flow with color or power Doppler

Prostate cancer

Most common cancer in American men

•Second most deadly male cancer

•Patients have an abnormal PSA level – greater than 4 ng/mL

•PSA is primary test for assessing risk of developing prostate cancer

•Can be elevated in BPH and prostatitis

•Sonography-guided Bx is used for definitive diagnosis

•Trans-rectal ultrasonography (TRUS) is used to evaluate zonal anatomy

•Peripheral zone is location of 70% of prostate cancers

•Cancer may spread to central zone, ejaculatory ducts, or cause dilated seminal vesicle