4.3 Testis and Penis

Question 1

Vas deferens course

Answer 1

Posterior aspect spermatic cord, diverges at deep inguinal ring, passing anterior to internal iliac artery, forming ejaculatory duct with seminal vesicle at prostatic base

Question 2

Contents of Spermatic cord

Answer 2

vas deferens, vessels, lymphatics (drain to lateral and preaortic nodes) and nerves

Neurovascular bundle in spermatic cord:
Internal spermatic (tesicular - aorta), external spermatic (cremasteric - inferior epigastric) and differential arteries (to epididymis and vas - vesicular branch of internal iliac)
Pampiniform plexus drains to ipsilateral testicular vein
Nerves: cremasteric nerve, genital branch of genitofemoral nerve and testicular sympathetic plexus

Question 3

Testicular embryology

Answer 3

Genital ridges extend from T6 to S2
Mesenchyme between seminferous tubules forms Leydig cells (begin to secrete testosterone at 8 weeks)
Mesonephric ducts form epididymis, vas deferens, seminal vesicles and ejaculatory ducts, while paramesonephric ducts regress
At 7-8 weeks, testes descend to pelvis, staying at deep inguinal ring until seventh month, then descend to scrotum

Question 4

Epididymitis

Answer 4

Commonest postpuertal acute scrotal pathology, likely ascending infection (gonococcal, E Coli, pseudomonas, TB); 20% develop orchitis
Acute US: Swollen hyperaemic (only sign in 20%) hypoechoic epididymis (>5 mm thick)
Thickened scrotal skin ± hydrocoele (if complex suggests pyocoele)
Chronic US: Swollen epididymis ± hyperechoic

Question 5

Orchitis

Answer 5

Commonest complication of mumps infection in postpubertal males (in which case usually unilateral); causes unilateral atrophy in one third, bilateral in 10%; atrophy detectable by 6 months

US: Enlarged, hypoechoic (usually), hyperaemic testis
Focal orchitis does not distort testicular contour (unlike cancer)

Question 6

Varicocoele

Answer 6

L (95%) > R, 25% bilateral; if solitary on right - concern for RP malignancy
Abnormal dilatation pampiniform plexus, causing compressible scrotal veins > 2 mm diameter, more prominent on valsalva or standing

Question 7

Testicular Ca types

Answer 7

Germ cell [SpECT] (95%; metastases may have different histology from original tumour):
Seminomas (40%) - do not cause elevated AFP; homogenously hypoechoic, usually focal but may be diffuse, sharp interface with normal parenchyma; radiosensitive
Mixed (40%) - teratocarcinoma is commonest
Non-seminomatous GCT (more aggressive)
Embryonal Cell Carcinoma (10%) - cystic, heterogenous, ‘wild’
Teratoma (10%)
Choriocarcinoma (1%, aggressive, early haematogenous metastasis, frequently to brain)
Yolk sac carcinoma

Non-germ cell (5%; 'sex cord'; usually benign)
Leydig cell (can produce testosterone, 30% cause virilisation / feminisation)
Sertoli cell (can produce oestrogen and present with gynaecomastia)

Lymphoma (most common tumour in older men, may be bilateral) - less distinct margin

Metastases
Prostate, lung, kidney, GIT, myeloma, leukaemia

Question 8

Testicular Ca lymph nodes

Answer 8

Sentinel LNs
Left - left renal perihilar group (just below left renal vein)
Right - paracaval LNs at or below right renal vein
Haematogenous spread is most commonly to lungs; then liver, bone and brain

Question 9

Testicular Ca Staging

Answer 9

Low: confined to testis / epididymis / spermatic cord (T1-3), mild / moderate LNs (N1-2)
Advanced: invades scrotal wall (T4), RP LNs (N3), visceral metastases (M1)

Question 10

Testicular calcifications

Answer 10

Microlithiasis:
0.6% males, in 50% with germ cell tumours
1-2 mm calcifications in seminiferous tubules
Associations with cryptorchidism, Kleinfelter’s, Down Syndrome

Large calcifications:
Tumours - teratocarcinoma, seminoma, embryonal cell, Serrtoli and Leydig cell
Teratoma - large, irregular calcifications
Miscellaneous - treated cancers, old infections, haematomas, infarcts

Question 11

Locations of undescended testis

Answer 11

Occurs in 0.3% adult males; higher risk of torsion and malignancy (x30 risk)
Root of scrotum (50%)
Inguinal canal (20%)
Abdominal (10%) - anywhere between lower pole of kidney and internal ring
10% bilateral

Question 12

Testicular torsion

Answer 12

Extravaginal (fetus / neonatal): twisting of testis, epididymis and tunica vaginalis in spermatic cord

Intravaginal (usually peripubertal): associated with bell clapper deformity (tunica surrounds testis - 12% males)
10% bilateral, difficult to palpate testis; Doppler approaches 100% Sn; at > 4 hours enlarged and heterogenous on greyscale, usually nonsalvagable at > 24 hours.

Question 13

Seminal vesicle agenesis

Answer 13

Unilateral SV agenesis usually due to insult before 7th week in utero, thus associated renal abnormalities:
Ipsilateral renal agenesis (80%)
Other renal abnormality (10%)
Normal kidney (10%)

Bilateral SV agenesis - CFTR mutation in 60%, associated with bilateral vas agenesis, usually normal kidneys

Question 14

Penile cancer

Answer 14

Higher risk if uncircumcised (3/1), phimosis (25%), chronic balanitis, UVA treatment, HPV
Usually SCC (95%), sarcoma (including Kaposi), melanoma, BCC, lymphoma
Rarely metastatic, usually from a urogenital source
MR Gd+ for local staging