Undescended Testis
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Direct answer
Undescended testis, or cryptorchidism, is a testis that has not reached the dependent scrotum and is one of the commonest genital problems in boys. A retractile testis moves freely and stays in the scrotum once brought down, whereas a true undescended testis cannot be brought down. Orchidopexy is ideally performed between six and twelve months of age, protecting fertility and reducing, though not removing, malignancy risk.
What you must remember
- Definition: a testis outside the dependent scrotum, either palpable in the inguinal canal or impalpable, where it may be absent, atrophic or intra-abdominal.
- Retractile testis: a normal variant that can be manipulated into the scrotum and stays there, requiring observation rather than surgery.
- Spontaneous descent: many testes in full-term newborns descend within the first few months, so the surgeon reassesses before deciding on surgery.
- Timing: orchidopexy between about six and twelve months, ideally before the end of the first year.
- Risks: infertility and testicular germ cell tumour risk are higher, and orchidopexy reduces but does not remove them.
- Associations: hypospadias and inguinal hernia commonly coexist, and disorders of sex development must be considered when genitalia are ambiguous.
- Impalpable testis: laparoscopy is the standard assessment, since ultrasound has limited sensitivity.
A stepwise approach from examination to orchidopexy
Undescended testis is usually found on routine newborn examination. The steps below separate normal variants from true disease and set the timing of surgery.
- Examine warm and relaxed: in a warm room, with the child supine and the legs abducted, a retractile testis slides into the scrotum and stays there.
- Classify the position: a palpable testis in the canal is inguinal, whereas a non-palpable testis may be absent, atrophic or intra-abdominal.
- Reassess early: a testis undescended at birth is reviewed over the first several months, as spontaneous descent is common.
- Image or scope when needed: ultrasound is useful but limited, and laparoscopy is the standard assessment for the impalpable testis.
- Operate in the first year: orchidopexy at about six to twelve months mobilises the cord and places the testis in the scrotum.
- Follow up: check testicular position, size and growth, and continue to review the testis after surgery.
- Counsel the family: explain that fertility and malignancy risks are reduced by surgery but not removed, and that lifelong testicular examination is advised.
Where the exam tries to catch you
Undescended testis questions test the difference between normal variants and disease, and the correct timing of surgery.
- Trap: operating on a retractile testis as if it were undescended. Correct: a retractile testis stays in the scrotum after manipulation and usually needs only observation.
- Trap: believing orchidopexy removes the malignancy risk. Correct: it reduces but does not remove the risk, so lifelong self-examination and follow-up still apply.
- Trap: waiting until school age for spontaneous descent. Correct: spontaneous descent is unlikely after the first year, so surgery should be planned before then.
Frequently asked questions
What is the difference between a retractile and an undescended testis?
A retractile testis can be manipulated into the scrotum and stays there, whereas a true undescended testis cannot be brought down and remains outside the scrotum. Retractile testis is a normal variant and does not need routine surgery.
At what age should orchidopexy be performed for undescended testis?
Orchidopexy is ideally performed between six and twelve months of age, before the end of the first year. This window is favoured in standard texts because it protects fertility and reduces malignancy risk.
Why does undescended testis reduce fertility?
Undescended testis reduces fertility because a testis outside the scrotum is exposed to a higher temperature than the scrotum, which impairs germ cell development. Early orchidopexy improves the outcome, but fertility can still be reduced.
Which investigation is used for an impalpable testis?
Laparoscopy is the standard investigation for an impalpable testis, because it can locate the gonad and allow orchidopexy in the same procedure. Ultrasound is useful but has limited sensitivity for an impalpable testis.
Which other anomalies commonly accompany undescended testis?
Hypospadias and inguinal hernia commonly accompany undescended testis, so the genitalia are examined carefully at every review. Disorders of sex development should be considered when an impalpable testis is accompanied by ambiguous genitalia.