Undescended Testes

Congenital and acquired undescended testes (UDT) can cause infertility; congenital UDT left untreated also increases testicular cancer risk. See also paediatric surgical conditions for the hernia/hydrocele/UDT differentiation table and referral timeframes.

Definitions

Diagnosis is clinical — the testis isn’t found in the scrotum. Acquired = previously descended, now not; congenital = born undescended. Ultrasound is not routinely useful for localising a nonpalpable testis.

• Retractile testis — usually toddlers/pre-pubertal boys. Normal size, mostly resides in the scrotum but retracts from an exaggerated cremasteric reflex; can be manipulated down and stays there for a while. Carries an increased risk of becoming acquired UDT (an “ascending” testis).
• Undescended testis — cannot sit in the scrotum unassisted; if manipulated down, retracts back out on release. Often subtly smaller than the contralateral testis, with a slightly underdeveloped ipsilateral hemiscrotum.

Surveillance schedule

• Congenital UDT: examine at birth and 3 months; monitor monthly if found; refer for treatment if persistent between 3–6 months.
• Acquired UDT: to avoid missing it, examine yearly from age 1–3, then every 2 years from age 3–10. Persisting >6 months in a previously descended testis → refer to a paediatric surgeon.

Management

Mainly surgical correction (orchidopexy) in a timely manner — hormonal therapy is not recommended in Australia.

• Orchidopexy is indicated for acquired UDT (testis was in the scrotum for the first 3–6 months but is later found outside it) — cause is usually the spermatic cord failing to elongate with pelvic growth, or a persistent fibrous processus vaginalis remnant.
• Infertility risk relates to germ-cell degeneration from the higher intra-abdominal temperature (35–37°C) vs scrotal (33°C), which inhibits postnatal germ cells transforming into spermatogenic stem cells around 3–6 months of age — this also drives the increased cancer risk.

Referral

• Ambiguous genitalia or suspected disorder of sexual differentiation (e.g. UDT + severe hypospadias, absent testes bilaterally) → urgent joint paediatric urology + paediatric endocrinology referral.
• Testes not descended by 3 months (corrected age) → refer; orchidopexy likely if persistent UDT beyond 6 months.
• Testes not palpable in groin or scrotum → refer for possible laparoscopic exploration.
• Retractile testis: review 6-monthly; refer if persistently retractile beyond age 2, or if it becomes ascended at any stage.
• Acquired UDT not resolving after 3 months → refer.
• Educate boys around age 10–12 about a prior UDT history and the importance of regular testicular self-examination.