see also:

• acute scrotal pain or swelling
• groin herniae
• RCH Kid's Health Info
• Vic Better Health Channel

• 5% of boys are born with an undescended testis, especially premature babies, whilst some boys develop undescended testes from age 1-10yrs as they grow faster than the spermatic cord
• undescended testes, particularly if left untreated, increases risk of testicular cancer (up to 20-40x risk with half of all tumours resulting from intra-abdominal testicles) and infertility

• retractile (hyperactive cremaster)
• by site:
  • ectopic testis (8%)
  • true undescended testis:
    • intra-abdominal (10%)
    • intracanal (61%)
    • emergent (18%)
  • absent (3%)
    • may be associated with prenatal torsion testes or birth defects affecting the urologic system
• unilateral (90%) / bilateral (10%)
• congenital:
  • born with undescended testes (5% of boys born)
  • especially premature neonates as descent usually occurs at 25-35wks
    • 17% of male newborns that weigh under 2.3kg have undescended testicles
    • all male newborns that weigh under 907g have undescended testicles
  • other factors include:
    • failure of descent setting at 8-14 wks pregnancy
    • those with hormonal or genetic issues
      • Down syndrome, Prader-Willi syndrome, and Noonan syndrome.
    • maternal diabetes or obesity
    • cigarette smoking, alcohol consumption during pregnancy
    • maternal use of non-steroidal anti-inflammatory drugs (NSAIDs) or paracetamol (acetaminophen) may increase risk
    • prenatal exposure to a chemical called phthalate (DEHP) may be associated with increased risk
    • FH undescended testis
• acquired:
  • can happen at 1-10 years age
  • as the boy grows the spermatic cord, fails to grow at the same rate. It ends up too short and pulls the testes back up into the groin.

• is there suggestion of past groin herniae
• position of testicle at birth
• position of testicle at bath time

• be patient and use warm hands
• check appearance of phallus and scrotum
• bimanual palpation of testicle: milk toward scrotum
• cough impulse
• apply abdominal pressure
• examine with child standing and squatting
• assess testicular size - is there compensatory hypertrophy?

• usually none
• USS, CT scan, venogram or renal USS not indicated
• refer to paediatric surgeon who may Ix or Rx as follows:
  • laparoscopy for impalpable testicle
  • chromosome analysis
  • hormone analysis
    • FSH, LH, testosterone, HCG stimulation test
    • only for bilateral impalpable/atrophic testes
  • orchidopexy - usually at one year of age
  • orchidectomy
  • insertion of prosthesis

• 1762: J. Hunter - noted gubernaculum causes testicular descent
• 1899: AB Bevan - spermatic cord mobilisation
• 1909: F Torak - fixation of testicle
• 1931: Petrivalsky - Dartos pouch
• 1959: Fowler Stephens - stage procedure, testicular vessel division
• 1970's: microvascular technique
• 1980's: laparoscopy
• 1990's: use of HCG injections in Rx
• 2000's: use of GnRH analogs in Rx
• 2008: study linking risk with phthalate (DEHP) exposure
• 2010: study linking risk with non-steroidal anti-inflammatory drugs (NSAIDs) and paracetamol (acetaminophen)

• 5th week: gubernaculum - condensation of mesenchyme at caudal end of the mesonephros
• 7th week: primitive germ cells - from the endoderm of yolk sac, migrate along the dorsal gut mesentery
• 8th week: Sertoli cells 1st seen in testicular cords and Leydig cells noted in testicular interstitium
• 8-14th week: it appears testicular descent status is “set” during the 8-14 weeks of gestation in humans. Undescended testis is a result of disruption in androgen levels only during this programming window.
• 14th week: canalisation of sex cords begins; proliferation of Leydig cells start
• 25-35 weeks: descent usually occurs in 8th month of pregnancy and involves:
  • gubernaculum
  • unfolding
  • Mullerian Inhibitory substance
  • intra-abdominal pressure
• 1st 6 months after birth:
  • further descent of the testes into the scrotum occurs. This is attributed to the postnatal surge of gonadotropins and testosterone that normally occurs between the first and fourth months of life.