Prostate and penile anatomy, USA, and pathology

Prostate anatomy

Flattened cone shaped, retroperitoneal organ

Base is superior portion of gland sitting below inferior margin of bladder

Apex is inferior portion that sits superior to the urogenital diaphragm

Prostate is bordered by

Bladder superiorly

Urogenital diaphragm inferiorly

Pubic bone anteriorly

RectuM posteriorly

Anterior prostatic fat/fascia separates the prostate anteriorly form…

The pubic bone

Levator Ani and ____________ support the gland laterally

Obturator internus

_________________ separates prostate from rectum

Denovillier fascia

Anterior prostate is attached to the symphysis pubis and pubic bone by

Puboprostatic ligaments

Each _____________ empties spermatic fluid into an ejaculatory duct of the ipsilateral seminal vesicle

Vas deferens

Right and left ejaculatory ducts pass through __________ of prostate and into the urethra

Central zone

Verumontanum

Longitudinal ridge within urethra that holds the openings from the ejaculatory ducts

Internal iliac artery - Inferior vesicular arteries:

Small perforating arteries

Perforating arteries follow nerve branches for erection, form__________

Neurovascular bundles

Anterior plexus of __________ merges with dorsal penile vein to drain venous blood into the internal iliac vein

Santorini

Prostate Zone 1: Transitional

5% of the glandular tissue

Central zone surrounding proximal prostatic urethra

2 lobes, one on each side of the urethra

Superolateral to verumontanum - area where ejaculatory ducts enter urethra

20% of cancers originate here

95% of BPH originates in this zone

Prostate Zone 2: Central zone

20% of glandular tissue

At base of glands, posterior to urethra

Narrows to a peak at the area posterior to verumontanum

Seminal vesicle and vas deferens ducts merge to form ejaculatory ducts

Ejaculatory ducts coarse through this region to join the urethra

10% cancers originates in this zone

Prostate Zone 3: Peripheral zone

70% of glandular tissue

Posterior and lateral to the distal prostatic urethra

70% of cancers originate here

Less common site for BPH

Prostate Zone 4: Periurethral Glandular zone

Glandular tissues that line the proximal prostatic urethra

Fibromuscular region

Previously called the anterior zone

Thick sheath covering entire anterior prostate surface

Size of the sheath equates to up to 1/3 the size of the gland

Made of smooth muscle and fibrous tissues

NO glandular tissue = NOT affected by cancer, inflammation or BPH b/c it is NON FUNCTIONAL prostatic tissue

Prostate physiology

Secretes an alkaline fluid that is included in the male ejaculate

Acinar cells produce PSA which is measured to assess prostate health

Prostate-specific antigen (PSA)

Produced by acinar cells

Measured to assess increasing levels of benign and/or malignant tissue

Normal levels usually range from 0ng/ml to 4ng/ml

Levels >10ng/ml usually related to malignancy

Varies with patient age, gland volume, BPH or malignancy

Cancer elevates the PSA much more significantly than BPH

True/False: Not all prostate cancers cause an elevation of PSA

True

Prostatic acid phosphatase (PAP)

Elevated with prostatic cancer

Seminal vesicle anatomy

Paired pouch-like glands that the base of the bladder

Superior and posterior to prostate

Posterior inferior to the bladder and anterior to the rectum

Store sperm and secrete fructose for ejaculation

Secretions mix with prostatic fluid to form semen during ejaculation

Seminal vesicle physiology

Secretes fructose to provide an energy source for sperm and alkalinity to enhance sperm mobility

TA prostate evaluation required a ________ bladder

Full

Transrectal prostate approach

Usually performed only as a Bx guidance since PSA screening was started

Position for Transrectal ultrasound

Pt placed in LLD or lithotomy position

Prostate volume equation

Length x Width x Height x 0.52

USA prostate

Homogenous mid-level grays

Symmetric oval shape

Smooth

Peripheral zone appears slightly hyperechoic to adjacent parenchyma

Eiffel tower sign

Normal prostate volume

<30mL

USA seminal vesicles

Hypoechoic compared to prostate

Diamond or oval shape

Irregular borders

Seminal vesicles

Transrectal prostate

Transabdominal prostate

Benign prostatic hypertrophy (BPH)

Begins as early as 30 yrs of age

Related to testosterone

95% occurs in transitional zone

Increase in gland size

Formation of nodules, may have cystic changes

Corpora Amylacea - benign calcs in central gland caused by waste products collecting acinar cells

Benign prostatic hypertrophy (BPH) Symptoms

Urinary frequency, nocturia, weak urine system, incomplete emptying

Benign prostatic hypertrophy (BPH) causes increase in _____ levels

PSA

Normal PSA levels

0ng/mL - 4ng/mL

USA Benign prostatic hypertrophy (BPH)

Early stages - Inner gland more coarse than peripheral/central zones

Punctate calcifications

Diffuse enlargement

Later stages - nodularity more evident, more calcs, necrosis of cysts

Increased color Doppler in inner gland

Eval kidneys - enlarged prostate can cause urine retention in bladder and hydro

Benign prostatic hypertrophy

Inflammation/Prostatitis

Bacterial or non-bacterial cause

Prostadynia

Fever, pain, urinary frequency/urgency/difficulty

USA Inflammation/prostatitis

Heterogeneous peripheral gland

Hypoechoic halo at the periurethral area

Abscess formation can occur later

Marked hypervascularity

Eval kidneys

Prostatitis

Prostate abscess

Cysts in prostate

Congenital or acquired

Ejaculatory duct cyst can lead to infertility

Simulate cancer on manual rectal exam

Typical cystic characteristics, round, smooth border, anechoic with posterior enhancement

Prostate cyst

Calcifications

Corpora amylacea refers to calcs commonly seen in central zone

Can be related to prior infection

Can be single or multiple

Corpora amylacea

Extra-capsular carcinoma

Limits treatment and decreases survival

PSA levels significantly elevates

PAP levels elevates

Most common after 65yrs and in African American men

Family Hx increases risk

70% in peripheral zone, 20% in transitional zone, 10% central zone

Trans rectal used to measure prostate volume and guide for Bx

Most frequently diagnosed malignancy in a male

Extra-capsular prostate carcinoma

PSA levels 4-10ng/mL

Suspicious for malignancy

PSA levels >10ng/mL

Highly suspicious for malignancy

Prostate Bx

INR levels should be <1.5 to prevent increased risk of hemorrhage from Bx

Pt is placed in decubitus position

Spring loaded Bx device is used to obtain the sample

UTI is contraindication

USA Extra-capsular prostate carcinoma

Focal mass

Most commonly hypoechoic

Only 50% of hypoechoic prostatic masses are cancer

Mat see some shadowing from dense masses

Peripherally oriented mass formation (peripheral zone)

Intra-capsular prostate cancer

Difficult to diagnose

Usually detected by four quadrant Bx

Intra-capsular prostate cancer USA

Bulging of capsule

Disruption of tissues

Hypervascularity

Prostate cancer

Brachytherapy

Used in non-aggressive in situ cancers

Surgical implantation of radioactive seeds into prostate

Sequential scan performed to obtain volume and shape of prostate

Determines number of seeds and seed distribution

Identifies arch interference that limits access to gland for seen implantation

US used to monitor

Brachytherapy

Corpus cavernosa

Two main erectile structures of the penis

Sinusoids fill with blood during erection

Covered by tunica albuginea

The right and left cavernosal arteries course through the right and left CC

Glans penis extends over ends of corpora cavernosa

Corpus spongiosum

Urethra and urethral arteries travel through this portion

Covered by tunica albuginea

Internal iliac arteries give rise to the internal pudendal arteries, bulbourethral artery, and ___________

Penile arteries

The penile artery branches into the _____________ and cavernosal arteries

Dorsal

Right and left cavernosal arteries enter the right and left ___, respectively

CC

The __________ arteries are multiple tiny branches of the cavernosal arteries that penetrate tissue

Helicine

Superficial dorsal vein and ________ vein provide the primary venous outflow

Deep dorsal

Indications for penile exam

Erectile dysfunction, priapism, peyronie disease, palpable areas, trauma

Erectile dysfunction

Inability to achieve a full and persistent erection

Can be caused by vascular insufficiency

Other causes include obesity, diabetes, metabolic syndromes, certain medications, peyronie disease, enlarged prostate

Cavernosal artery diameters and velocities are evaluated before and after injection of vasoactive substance

Dorsal vein is also evaluated after injection

Priapism

Unwanted, persistent, painful erection that lasts more than 4 hours

Spontaneous or caused by certain medications

Excessive arterial inflow with inadequate venous outflow

PW used for diagnosis

Requires immediate treatment

Peyronie disease

Development of scar tissue and fibrous plaque formation that usually involves the tunica albuginea

Causes restriction and curvature of the affected side of the penis during erection

Can be painful

Hyperechoic areas along the outer margins of the corpus cavernosa

Peyronie disease

Penile cancer

Identified on the glans penis or on the foreskin in uncircumscribed men

Most common cancer to affect penis is SQUAMOUS CELL carcinoma

Focal mass is present

Solid and hypoechoic with irregular borders and internal vascularity

Penile cancer Symptoms

Focal area of skin thickening, palpable lump, an ulcer that may bleed, reddish, velvety rash under foreskin, flat, bluish-brown growths, odorous discharge or bleeding underforskin

Penile trauma

Fracture of penis can occur with blunt force during an erection

Corpus cavernosum on one or both sides can be fractured causing subcutaneous bleeding and significant pain

Pts usually describe a pooping sound that occurred curing intercourse followed by significant pain

Ultrasound can be helpful in identifying damage to the soft tissues, vascular and urethra structures

The base of the prostate is just inferior to the _________, while the apex is just superior to the ________

Bladder, urogenital diaphragm

Blood supply to the prostate comes from

Internal iliac arteries

Benign prostatic hypertrophy is most commonly identified in the _________zone, while prostatic cancer is most commonly identified in the_____________zone

Transitional, peripheral

What portion of the prostate is unaffected by inflammation and cancer

Fibromuscular

What is the minimum PSA level that indicates prostatic cancer?

>10ng/mL

The seminal vesicles secrete:

Fructose

_________ should be taken before a prostate Bx, while ________ should be stopped at least 5 days before the procedure

Antibiotics; warfarin

Term used for the shadowing created by dense tissues in the area of the urethra and verumontanum

Eiffel tower sign

The Gleason score is used to classify:

Aggressiveness of carcinoma

2 primary arteries that supply the penis with blood

Dorsal and cavernosal

2D imaging of the penis is used to evaluate _________, while PW Doppler is used to identify ________.

Peyronie disease; Vascular insufficiency

What structure is fractured in cases of penile trauma

Corpus cavernosum