Urology

Question 1

Formation and descent of the testicle

Answer 1

1. Gonadal ridge
2. Guided by gubernaculum
3. Descent to deep inguinal ring by 4 months
4. Start passage from deep inguinal ring at 7 month
5. Testicle draws with it peritoneum - processus vaginalis which should obliterate..
6. Clinical relevance
   * Maldescent of testicle
   * Hernia and hydrocele
   * Referred pain and lymphatics

Chromosomal (genetic) sex determines gonadal sex
Gonadal sex in turn modulates phenotypic sex through endocrine action (hormones)
If a testis develops, the urogenital tract becomes masculinized, and if an ovary (or no gonad) is present, the urogenital tract is feminized.

Formation of the gonad
o Gonad formed at the gonadal ridge
 Primordial germ cells
 Migrate from the yolk sac to the
 Ventral aspect of the posterior abdominal wall
 Medial to mesonephros
 Coelomic epithelium and sex cords
 Gonads appear phenotypically the same at this point
 Then
* Males
o SRY protein  differentiation into testicle
o Testicle
 Leydig  testosterone  differentiation of mesonephric/wolffian duct into vas, epididymis and seminal vesicles
 Sertoli  anti-Mullerian hormone  degeneration of the Mullerian duct (appendix testis)
o A thick condensation of mesodermal cells (gubernaculum) tethers the lower pole of the testicle to the anterior abdominal wall, the part which will subsequently become the scrotum

Testicular Descent
* Two (morphologically and hormonally) distinct stages.
o The first stage of testicular descent = transabdominal
* Weeks 8 to 15
* Movement of the testes from their starting position on the posterior abdominal wall adjacent to the kidney down to the deep inguinal ring
* Dependent on a non-androgenic hormone (insulin like factor 3-INSL3)
* The gubernaculum, enlarges caudally, leading to the formation of the gubernacular bulb
* 10th to 15th gestational weeks, the cranial suspensory ligament (CSL) regresses
o Inguinoscrotal Stage
o From 26th gestational week
o Androgen-dependent
o Passage of the testes from the internal inguinal ring down into the scrotum
o Includes
 The formation of the processes vaginalis from abdominal peritoneum
 Dilation of the inguinal canal by the gubernacular bulb
 Abdominal pressure to push the testes through the inguinal canal

Question 2

Layers of the scrotum and origins

Answer 2

o Skin - Skin
o Scarpas - Dartos
o External oblique aponeurosis – External spermatic fascia
o Internal oblique muscle - Cremaster
o Transversalis fascia - Internal spermatic fascia
o Peritoneum - Tunica vaginalis
o Tunica albicans

Question 3

Contents of spermatic cord

Answer 3

Contents of spermatic cord:
- The layers as above
- Artery
o Testicular
o Cremaster (from inferior epigastric)
o Vas
- Vein
o Pampiniform
- Vas
- Processus vaginalis
- Nerve
o Genital branch of genitofemoral
o Sympathetic
- Lymphatics
- Fat/lipoma

Question 4

Draw the testicle

Answer 4

Question 5

Types of testicular cancer

Answer 5

• Definition:
  o Primary; 95%
• Germ cell tumours
• Non germ cell tumours
  o Secondary
   Lymphoma
   Metastasis
• Incidence/epidemiology:
  o 2nd most common cancer 18-39 years
  o 15-35 most common
• Aetiology & risk factors:
  o Cryptoorchidism
  o Klinefelter’s syndrome XXY
  o Infection (HIV, mumps)
  o Family history
  o Previous radiotherapy
• Pathophysiology:
  o Primordial germ cells
   Seminomatous tumours (seminoma)
   Non seminomatous tumours
• Faster, aggressive
• Metastasis early
• Variable response to treatment
• Subtypes
  o Mixed
  o Embryonal
  o Teratoma
  o Yolk sac
  o Choriocarcinoma
• bHCG, AFP
  Non germ cell tumours
   Sertoli cell tumours
   Leydig cells tumours

Question 6

Seminoma

Answer 6

Primary - germ cell - seminoma
* Slow growth
* Metastasis late
* Respond well to radiotherapy
* Good prognosis
* bHCG levels
* Subtypes (mneumonic) CAS
o Classic
o Anaplastic
o Spermatocytic

Question 7

Varicocele grading

Answer 7

1. Palpable on valsalva only (not visible)
2. Palpable on standing (not visible)
3. Visible on gross inspection