Undescended testicles

Definition
Undescended testicles, or cryptorchidism, is a condition where one or both testes fail to descend into the scrotum before birth or within the first few months of life. It is the most common congenital abnormality of the male genitalia.

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Normal Testicular Descent

• Occurs in two phases during fetal development:

  1. Transabdominal phase (8–15 weeks gestation) – controlled by anti-Müllerian hormone

  2. Inguinoscrotal phase (25–35 weeks gestation) – driven by androgens

• In full-term newborn boys, testicular descent should be complete; in preterm boys, descent may still be ongoing at birth.

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Types

• True undescended testis – located along the normal path of descent (intra-abdominal, inguinal canal, just outside external inguinal ring)

• Ectopic testis – deviated from the normal path (perineum, femoral canal, superficial inguinal pouch)

• Retractile testis – normally descended but can move into groin due to overactive cremasteric reflex; not true cryptorchidism

• Acquired (ascending) testis – previously descended testis that later becomes undescended due to spermatic cord not elongating with growth

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Epidemiology

• Present in ~3% of full-term male newborns, ~30% of preterm males

• Most descend spontaneously within 3–6 months after birth

• Persistent undescended testis at 6 months: ~1% of boys

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Causes / Risk Factors

• Premature birth

• Low birth weight or small for gestational age

• Family history of cryptorchidism

• Maternal smoking, alcohol, or pesticide exposure during pregnancy

• Hormonal disorders (androgen insensitivity, gonadotropin deficiency)

• Abnormal anatomy (short spermatic cord, adhesions)

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Clinical Features

• Empty scrotal sac or asymmetry

• Palpable testis in the groin or abdomen, or non-palpable testis

• May be unilateral or bilateral

• Usually asymptomatic in infants; later risk of complications

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Complications

• Reduced fertility – impaired spermatogenesis from prolonged higher intra-abdominal temperature

• Testicular cancer – 3–8× increased risk (especially seminoma)

• Testicular torsion – more likely with abnormal position

• Inguinal hernia – common association

• Psychological and cosmetic issues

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Diagnosis

• Physical examination – palpation from inguinal canal toward scrotum

• Imaging (not routine before surgery unless testis is non-palpable):

  • Ultrasound (low sensitivity for intra-abdominal testes)

  • MRI or diagnostic laparoscopy for non-palpable testis

• Hormonal tests in bilateral non-palpable cases to rule out anorchia or DSD (disorders of sex development)

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Management

1. Observation

• Many testes descend spontaneously by 3–6 months of age (corrected for prematurity)

• No descent by 6 months → intervention recommended

2. Surgical – Orchidopexy

• Performed ideally between 6 and 12 months of age

• Mobilises testis and secures it in scrotum

• Improves fertility potential, facilitates cancer surveillance, reduces torsion risk

3. Hormonal therapy (less common, limited success)

• hCG injections or GnRH analogues – may be tried in select cases but less effective than surgery

4. Bilateral non-palpable testes

• Urgent evaluation to exclude life-threatening adrenal insufficiency or DSD

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Prognosis

• Best outcomes if orchidopexy is performed before 1 year of age

• Risk of infertility and malignancy remains higher than normal but is reduced with early correction

• Lifelong testicular self-examination advised after puberty