4.4 Prostate gland

Question 1

BPH - CFs, associations

Answer 1

50-75% males >60 y/o
More common in Blacks, HTN, DM
Involves transitional zone - glandular tissue surrounding prostatic urethra, at proximal end veru montanum

Question 2

Imaging findings BPH

Answer 2

IVP: ‘J-hook’ distal ureters (due to elevated interureteric ridge)
± ureteric dilatation / tortuosity if long-standing
bladder trabeculation / diverticula with prominent prostatic impression
US: Adenomatous nodules may appear as hypo-/hyperechoic regions; Can usually differentiate central and transitional zones
MR: Hyperplastic nodules high signal on T2W, can be low or high on T1W; Stromal proliferation gives low signal on T1W and T2W

Question 3

Imaging features of prostatitis

Answer 3

Low signal on T2W in peripheral zone, no focal mass or capsular irregularity
If chronic, can appear similar to cancer

Question 4

Gleason Grading of Prostate Cancer

Answer 4

Grade 1: well differentiated, Grade 5: Poorly differentiated (4 & 5 have potential for lymphatic spread)
Overall score is sum of two predominant histological patterns summated to give overall score (2-4 well differentiated, 5-7 moderately differentiated, 8-10 poorly differentiated)

Question 5

Prostate cancer - location, stage and US imaging appearances

Answer 5

85% located in peripheral zone
Tumour grading and size predict prognosis
Cancer elevates PSA x10 more than BPH
US: Usually oval hypoechoic lesion in peripheral zone (but only 10% of these are cancer)

Question 6

Prostate cancer MRI appearances

Answer 6

Axial T1W & T2W with sagittal T2W detects periprostatic extent
Tumours in peripheral zone show relatively low T2W signal (but non-specific)
T1W detects haemorrhage
Cancer shows early rapid enhancement then early washout
Criteria for extracapsular spread: neurovascular asymmetry, angulated gland contour, obliteration of retroprostatic angle
Spectroscopy - cancers show low citrate and high choline (thus elevated choline/citrate ratio >2 SD above average for peripheral zone)
Mucinous adenocarcinoma and small infiltrating cancers hardest to detect

Question 7

Prostate Cancer Staging

Answer 7

Stage - A: Occult, B: Confined to capsule (treated with radical surgery), C: Extracapsular spread, D: Distant metastasis
T stage
1: only on histology or DRE
2a: Less than half of one side; 2b: >half of one side
2c: both sides of prostate
3a: extracapsular extension without seminal vesicle invasion; 3b: seminal vesicle invasion
4: spread to sphincter / rectum / pelvic wall
M - 1: regional nodes; 1a: distant LNs; 1b: osseous; 1c: visceral disease

Question 8

Prostate cancer nodal and metastatic spread - LNs, osseous, visceral and PSA

Answer 8

LNs: Obturator, Internal and external iliac LN’s; 80% with nodal disease develop bone metastases at 5 years
Osseous: 85% osteoblastic, 5% lytic, 10% mixed; pelvis > lumbar > femur > thoracic;
PSA > 58 suggests bone metastases; PSA less than 20 and no bone pain - 0.2% risk bone metastases
Intrathoracic: 6% patients at first diagnosis; 25% patients with stage D have lung or pleural disease; Lymphangitis carcinomatosis more common than lung nodules