Overview
Also known as cryptorchidism, undescended testes describe the incomplete descent of one or both testes from the abdomen through the inguinal canal. Most cases are unilateral and around 30% of cases are bilateral.
Normal testicular descent involves the transabdominal phase and then the inguinoscrotal phase which are both mediated by androgens. If the transabdominal phase fails, the testis remains in the abdomen. If the inguinoscrotal phase fails, the testis remains between the deep inguinal ring and the scrotum.
Classification
- True undescended testis – absent in scrotum but somewhere along the path of the normal descent
- Ectopic testis – lies outside the normal path of descent (e.g. femoral region, perineum, penile shaft, or opposite hemiscrotum)
- Ascending testis – previously present in the scrotum but has ascended over time
- Absent or atrophic testis – missing or seen after birth but disappears
Causes
Overview
- Most cases are idiopathic
- Up to 30% of cases are associated with abnormalities in the hypothalamic-pituitary axis
- Genetic disorders (e.g. Kallman syndrome)
- Androgen insensitivity syndrome
Epidemiology
- Undescended testis is the second most common paediatric surgical condition after inguinal hernias
- The prevalence of undescended testes in term infants is up to 4.5% and is higher in preterm delivery
Management
Overview
- Unilateral descended testis:
- If <3 months old: watch and wait
- If ≥3 months old, refer to a paediatric urologist
- Ideally, they should be seen before 6 months of age
- Bilateral descended testes:
- Immediate referral to paediatrician within 24 hours as this may suggest a genetic or endocrine disorder
Complications
- Infertility
- Testicular cancer
- This may be up to 3 times more common in those with a history of undescended testes
- Testicular torsion
