Cryptorchidism (Undescended Testes)
Cryptorchidism, also known as undescended testes, is the incomplete descent of 1 or both testes from the abdomen through the inguinal canal into the scrotum.
Causes and Risk Factors
The exact underlying cause is unknown, likely multifactorial.
Risk factors include:
- 1st degree family history of cryptorchidism
- Low birth weight (<2.5 kg) and/or small for gestational age
- Preterm delivery
- Genetic syndromes (e.g. Prader-Willi syndrome)
- Disorders of sexual development
- Gonadal dysgenesis
- 5-alpha reductase deficiency
- Androgen insensitivity syndrome
Features that may suggest a disorder of sex development:
- Atypical external genitalia
- Hypospadias
- Micropenis (stretched penile length of <2 cm in the newborn)
- Bifid or unfused scrotum
- Bilateral unpalpable undescended testes
46XX with congenital adrenal hyperplasia can mimic a male with non-palpable testes, but they do NOT have true testes.
Classification
There are 4 main subtypes of cryptorchidism:
- Retractile testis (a normal variant): the testis has descended into the correct position but may be found above the scrotum, due to the cremasteric muscle pulling the testis up (often triggered by cold)
- Classic history: the testes are palpable during a warm bath
- True undescended testis: testis lies outside the scrotum but along the normal path of descent
- Possible locations include: abdomen, inguinal region
- Ectopic testis: testis lies outside of the normal path of descent and outside the scrotum
- Possible locations include: femoral region, perineum, penile shaft or contralateral scrotum
- Most common: superficial inguinal pouch
- Ectopic testis usually won’t descend to the correct position spontaneously
- Absent / atrophic testis
- The testis may be seen in the scrotum at birth, but then disappears later
Classification by presentation:
- Bilateral in up to 30% of cases
- ~80% of all undescended tests are palpable
Cryptorchidism (undescended testis) simply means that the testis is NOT located in its normal scrotal position. It does not necessarily mean the testis is absent or cannot be felt.
- The testis may still be palpable, e.g. in the inguinal canal or high scrotal region, but it is considered undescended if it cannot be brought down to remain comfortably in the scrotum.
- A non-palpable undescended testis may indicate an intra-abdominal testis or an absent / atrophic testis.
Ascending testis refers to a testis that has previously been present in the scrotum but has then moved to a higher position and no longer lies in the scrotum.
Screening and Assessment
Scenario: Infant and Onwards
Screen ALL male infants within 72 hours of birth
| Findings at the initial screening | Subsequent action |
|---|---|
| Bilateral non-palpable undescended testes and/or suspected disorder of sexual development | Refer urgently (within 24 hours) to a specialist (often paediatrics)
If a disorder of sexual development is excluded and the testes are not presented in the scrotum by 4-5 m/o, ensure the child is referred to paediatric surgery / urology to be seen by 6 m/o |
| Unilateral undescended testis | No immediate action, re-examine at 6-8 weeks of age
|
If there are bilateral unpalpable undescended testes at 6-8 weeks of age → urgent referral to paediatrician within 48 hours
Ideally, perform the screening / examination with the baby lying flat in a warm room with warm hands.
If there are unpalpable testis / testes, ask the carer whether the testis has ever been palpable (e.g. if the testis is palpable during a warm bath, this suggests a retractile testis, which is a normal variant)
If the testis is non-palpable:
- Attempt to use the fingers to ‘milk’ from the external inguinal ring to the scrotum along the inguinal canal
- Check the contralateral testis
- Check for an ectopic testis in the femoral, penile and perineal regions
Scenario: Onset in Childhood / Adolescent / Adults
Refer ALL cases to a specialist
- Both unilateral and bilateral cryptorchidism cases need referral
- Refer to paediatric surgery / paediatric urology / urology, depending on the patient’s age and clinical judgement
Management
Definitive management (of congenital cryptorchidism): surgical correction
| Timing of surgery | Ideally performed between 6-12 months of age
By the latest, before 18 months of age |
| Surgical approach | Standard: orchidopexy (mobilising the undescended testis and fixing it within the scrotum)
Management of non-palpable testis is slightly more complicated:
|
Advise on regular testis self-examination during and after puberty, due to increased risk of testicular cancer (even after surgical correction).
Post-pubertal cryptorchidism:
Orchidectomy may be considered, especially if it is unilateral and the other testis is normal in the scrotum, because the undescended testis has a higher malignancy risk and often poor fertility potential.
Hormone therapy is NOT routinely recommended for cryptorchidism alone.
Complications
Key complications:
- Impaired fertility and paternity rate (esp. in bilateral cryptorchidism)
- Normally, the scrotum has a lower temperature (compared to the core body temperature) to allow optimal spermatogenesis
- Undescended testes that remain in the abdomen, inguinal canal, or groin are at a higher temperature and may result in germ cell damage
- ↑ Risk of testicular cancer
- 6x risk in those who did not have surgical correction or treated >10 y/o
- 2x risk in those who had surgical correction before puberty
- Risk is higher in intra-abdominal testes and bilateral cryptorchidism
- ↑ Risk of testicular torsion
- Association with inguinal hernia
Successful surgical correction of cryptorchidism reduces the risk, but does not completely prevent complications.