Undescended testes/ Cryptorchidism

Normal testicular development in utero begins along the mesodermal ridge of the posterior abdominal wall. By 28 weeks, the right and left testes reach their respective inguinal canals and, by 28-40 weeks, each testis has usually reached the scrotum.

An undescended testis is a testis that is absent from the scrotum. The term cryptorchidism, from the Greek kryptos (hidden) and orchis (testicle), is also used.

Absence may be due to:

  • Testicular agenesis (anorchia) – uncommon.
  • Retractile testis.
  • The ascending testis syndrome.
  • Testicular maldescent.

Retractile testes

  • Prepubertal boys can have an exaggerated cremasteric reflex.
  • The testis may retract out of the scrotum in the cold, on examination, on excitement or on physical activity.
  • It is normal and will descend when relaxed and warm, or it can be manipulated back into the scrotum.
  • Retractile testes do not need any treatment but do need close follow-up until puberty, as they can become ascendant.
  • Retractile testes have an increased risk of becoming an ascending or acquired undescended testis.

What are acquired undescended testes?

When a boy is born with his testes in the scrotum, they can occasionally move back out of the scrotum and into the groin. This is a condition called acquired undescended testes, or acquired cryptorchidism, which can happen between one and 10 years of age.

It is thought to be caused by the spermatic cords that attach each testis to the body not growing at the same pace as the rest of the body. The short spermatic cords slowly pull the testes out of the scrotum and into the groin.

What is an absent testis?

In about one in 20 cases of undescended testes, there is a complete absence of the testis. It is thought that an interrupted blood flow may cause the developing testis to die before birth.

An absent (or vanished) testis can also be associated with other birth defects of the urinary system, such as abnormal blood vessel networks to the vas deferens (the tubes that carry sperm).

Maldescended testes

  • These are usually unilateral.
  • The scrotum may be underdeveloped.
  • Maldescent may be due to an anatomical abnormality or due to hormone lack or hormone resistance. The release of testosterone from the fetal testis, the release of substances from an intact genitofemoral nerve and gonadotrophin hormone have all been cited as having possible involvement in normal testicular descent.
  • Most undescended testes migrate into the lower scrotum within the first three months of life, presumably as a consequence of a postnatal testosterone surge, with less than 1% remaining undescended by 1 year of age.
  • Descent can be:
    • Arrested – where descent is along the normal path but incomplete. The testis may be located near the pubic tubercle, in the inguinal canal (80%), or, uncommonly, in the abdomen. The testis is often small and abnormal with a short spermatic cord. There may be associated inguinal hernia.
    • Ectopic – where descent deviates from the normal path. The testis is most often found in the superficial inguinal pouch. Perineal, abdominal, pelvic, crural, penile and femoral positions are also all possible. The testis and spermatic cord are usually normal.

Undescended testes 2

What causes undescended testes?

Undescended testes can be unilateral (one) or bilateral (both), and are often found in babies with hormonal problems. Babies born with Klinefelter’s syndrome, spina bifida and Down syndrome are more likely to have undescended testes. However, for many babies the cause of undescended testes is unknown, although low levels of androgens (male sex hormones) during the prenatal period is suspected to be a common cause.

How common are undescended testes?

About one in 20 boys are born with undescended testes. This number drops to around one in 50 by six months of age because the testes often move into the scrotum during this time without any treatment. In some countries, the prevalence of cryptorchidism is thought to be increasing for unknown reasons.

  • This is by physical examination.
  • Around 70% of all undescended testes are palpable.
  • It can be difficult to distinguish undescended testes from retractile testis.
  • Imaging or ultrasound does not add any benefit to differentiating between palpable and non-palpable testes.
  • Examination should take place while the child is supine and in a cross-legged position. Cover the following steps:
    • Perform a visual examination of the scrotum.
    • Inhibit the cremasteric reflex with one hand above the symphysis in the groin region before touching the scrotum.
    • ‘Milking’ of the groin region towards the scrotum may help to move the testis into the scrotum. It can also help to differentiate between an inguinal testis and enlarged inguinal lymph nodes.
    • A retractile testis can usually be moved into the scrotum and will remain there until it retracts back into the groin again with a cremasteric reflex (eg, touching the inner thigh).
    • Look at the femoral, penile and perineal region for ectopic testes.
    • Diagnostic laparoscopy is usually the preferred method to confirm or rule out an intra-abdominal, inguinal or absent/vanishing testis (non-palpable testis). However, an examination under anaesthetic is often carried out before laparoscopy, as a previously non-palpable testis may become palpable.
    • Abdominal and pelvic ultrasonography may be required if intersexuality is suspected.
  • If, by the age of one year, descent has not occurred, spontaneous descent is unlikely. Treatment should be initiated, as there is also potential for histological deterioration and loss of testicular quality (may affect future fertility).
  • The ideal management of cryptorchidism is a highly debated topic within the field of paediatric surgery.
  • Treatment should be completed by 12-18 months of age.
  • However, despite early diagnosis in many patients with undescended testes, many are still referred and operated after 1 year of age.

Medical treatment

  • Testicular descent is hormonally dependent.
  • Treatment with human chorionic gonadotrophin (hCG) or gonadotrophin-releasing hormone (GnRH) can be used.
  • Success rates are best the lower the undescended testis is located.
  • Maximum success rates are 20%.
  • Medical treatment may be useful before or after surgery and may have a beneficial effect on later fertility.
  • However, hormonal treatment is not usually recommended anymore.
  • Side-effects of hCG treatment can include enlargement of the penis, pubic hair growth, increased testicular size and aggressive behaviour during treatment.
  • While some authors suggest that hormonal treatment increases the number and maturation of germ cells in cryptorchid testes, others believe the opposite. Studies have shown that hCG treatment may decrease sperm counts together wtih the future fertility potential.

Surgical treatment

  • The ideal management of cryptorchidism is still a highly debated topic within the field of paediatric surgery. Orchiopexy before 10-11 years may protect against the increased risk of testicular cancer associated with cryptorchidism. Orchiopexy should not be performed before 6 months of age, as testes may descend spontaneously during the first few months of life.
  • If the testis is palpable: an inguinal approach is usually used. Orchidopexy or orchidofuniculolysis (mobilisation of the testis and cord) can be performed. Success rates are up to 92%. Orchidopexy involves mobilisation of the testis on its essential structures (the vas, the testicular vessels and the spermatic cord) so that the testis can be brought down into the scrotum. The testis may also be fixed within the scrotum. Early surgical intervention in infancy may allow the normal development of stem cells for spermatogenesis. Some experts recommend that orchidopexy be performed between 6 and 12 months of age to maximise the future fertility potential and reduce risk of testicular cancer.
  • If the testis is non-palpable: examination under anaesthetic may reveal the previously non-palpable testis. The role of laparoscopy in the case of non-palpable cryptorchidism is both diagnostic and therapeutic. Laparoscopic orchiopexy for non-palpable testes is usually the preferred surgical approach among paediatric urologists. Removal, orchidolysis or orchidopexy can then be performed laparoscopically.

Why should undescended testes be fixed?

Undescended testes are linked to a range of health problems later in life.


The temperature in the scrotum is lower than in the abdomen, and sperm-producing tubes in the testes work better at this cooler temperature. If a testis is exposed to higher temperatures than when it is in the scrotum, it can affect sperm production.

Bringing the testis down into the scrotum between six and 12 months of age can improve fertility later in life. Men born with bilateral (both sides) undescended testes usually have very poor sperm quality, even if they are fixed by surgery.


The risk of developing testicular cancer is up to ten times greater than in the general male population. However, it should be noted that testicular cancer is uncommon.

Men have a higher chance of testicular cancer even after early placement of the testis into the scrotum. The normally descended testis opposite the undescended one also has a higher chance of developing cancer.


When a testis is trapped in an abnormal position it is at higher risk of injury or torsion (twisting and cutting off its blood supply). A testis in the scrotum has more movement and is less likely to be injured in ordinary activity.


A hernia sac, which is a lump that appears when tissue breaks through a weakened area of the abdominal wall, almost always happens with an undescended testis. If an operation is done to bring the testis into the scrotum, the hernia is found and fixed at the same time.

Poor self-image

As boys get older, body image becomes more important, especially during teenage years. Abnormal testes can have a negative impact on a boy’s confidence and self-esteem. Placing the testis in the scrotum makes the scrotum look normal.

Cosmetic appearance

  • Surgical transfer of the testis into the scrotum produces a better cosmetic appearance.
  • Prostheses may be used if the testis is removed. Prostheses should be implanted during adolescence.