Module 8 : Prostate Flashcards
prostate location
- inferior to bladder
- surrounds neck of bladder nd urethra
- posterior to pubis
- anterior to rectum
- levator ani muscle posterior
- fibrous capsule
prostate shape
- ovoid
- inverted pyramid
- apex = caudal
- base = cephalic
prostate size
- length = 3-3.5cm
- width = 4cm
- AP = 2-2.5cm
prostate weight
- younger under 50 = 20grams 20ccs
- older over 50 = 40 grams 40ccs
prostate function
- secretes alkaline fluid
+ 1/3 of semen volume
+ aids in sperm motility and activating sperm
+ neutralizes acid environment of vagina, uterus and Fallopian tubes - produces prostate specific antigen PSA
+ increases with age
anatomy
- zonal anatomy
- 4 zones in relationship to urethra and ejaculatroy duct
- useful in localization of cancer
- based on histological components
peripheral zone
- largest zone
- most common site of cancer
- surrounds distal urethra
- surgical capsule separates it form transition and central zone
- posterior lateral and apical regions
- benign prostatic hyperplasia (BPH) does not affect here
transition zone
- two small glands on either side of proximal urethra segment
- site of origin of benign prostatic hyperplasia
- ducts end in proximal urethra at level of verumontanum
central zone
- base of prostate
- ejaculatroy ducts pass through it
- resistant to disease process
- zone terminates near verumontanum
periurethral glands
- 1% of gland volume
- embedded in the longitudinal smooth muscle of pros urethrea
- internal prostatic sphincter
fibromuscular stroma
- non glandular area
- anterior surface of prostate
- one third of prostate
- smooth connection tissue
- NOT PART OF ZONES
outer/peripheral gland
- peripheral and central
inner gland
- transition zone
- fibromuscular stroma
- urethral sphincter
seminal vesicles
- paired ovoid
- posterior to bladder
- superior to prostate
- SV + vas deference = ED
- ED empty into urethra
- 3-4cm in length 1-3cm in thickness
indications for US
- DRE
- increased PSA
- urine infrequency , nocturne, decreased urine stream
- male infertility
- biopsy guidance
- blood or pus in urine or semen
transabdominal exam
- only for size and volume of prostate
- need full bladder
prostate on US
- ovoid
- low to moderate echoes
- homogenous
- echogenic interface from urethra
trans rectal TRUS
- variety of types
- end firing (viewing) probe most common
+ multiplane imaging
+ biopsy capability - probes covered in condom (latex or non latex)
- ## ASK PATIENT IF LATEX ALLERGY
TRUS scan technique
- empty bladder
- LLD position with legs bent to chest
- DRE performed prior to TRUS
- systemic approach axial and transverse
TRUS scan orientation
- rectum at the bottom of screen
- sag = anterior abdominal wall at top
peripheral zone sonographic appearance
- homogeneous and isoechoic
surgical capsule US look
- hypo echoic line
central zone US look
- hyper echoic or isoechoic to peripheral zone
transition zone US look
- isoechoic to peripheral zone
- hypo echoic with BPH
corpora amylacea
echogenic foci = collection of protein
periurethral glandular area US look
- hypo echoic
- blend with urethr
- prominent in young men
anterior fibromuscular stroma
- hypechoic
seminal vesicle
- hypo echoic
- symmetrical
- AP 10mm
what area used for standard echogenicity
peripheral zone
lab tests
- PSA
- PSA density
- Acid phosphate
- alkaline phosphate
prostate specific antigen PSA
- enzyme almost exclusively in prostate
- secreted and disposed of through ducts in prostate
- elevated in BPH infection carcinoma
- not specific to cause
- normal < 4ng/ml
- biopsy if >10ng/ml
PSA density
- PSA / prostate volume
- cancerous tissue produces more PSA
- density > 0.12 warrants a biopsy
acid phosphate
- found in prostate and semen
- increased in carcinoma that has spreadbeyon prostate capsule
alkaline phosphate
- produced in osteoblasts (bone) will increase if increase in osteoblast activity
- prostate cancer spread to bone
blood supply
- prostaticovesicle arteries
- brach of IIA
benign ductal ectasia
- 1-2mm tubular structure in peripheral zone
- hypoechoic
- can be mistaken for prostate cancer
calcifications
- incidental findings
- benign calcifications often coarser in appearance than malignant calcifications
