Undescended and Maldescended Testes

Normal testicular development in utero begins along the mesodermal ridge of the posterior abdominal wall. By the 7th month, the right and left testes reach their respective inguinal canals and by 9 months, 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

• Pre-pubertal 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.¹
• In one study, retractile testes had a 32% risk of becoming an ascending or acquired undescended testis.²

The ascending testis syndrome

• A previously normal or a retractile testis can become high with a shortened spermatic cord that prevents the testis from staying in the scrotum.
• Usually diagnosed aged 8-10 years.
• Some sources say that this needs corrective treatment³ but others suggest a 'wait-and-see' approach for spontaneous descent until puberty.⁴

Maldescended testes

• Are usually unilateral.
• The scrotum may be underdeveloped.
• Maldescent may be due to an anatomical abnormality or due to hormone lack or 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.
• 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%),⁵ or, uncommonly, in the abdomen. The testis is often small and abnormal with a short spermatic cord. 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.

• The most common congenital anomaly of the male genitalia.⁶
• A study looking at the birth prevalence of cryptorchidism in northern England from 1993-2000 found that it was 7.6 per 1000 live births.⁷
• There is a higher incidence in premature babies (up to 25%).³
• Affects almost 1% of all full-term male infants at the age of 1 year.⁶
• Unilateral cryptorchidism is four times more likely than bilateral.
• The right testis is more likely to be affected than the left.

Risk factors

Binge drinking⁸ or smoking during pregnancy,⁹ and mild gestational diabetes¹⁰ have all been proposed as potential risk factors for cryptorchidism.

• This is by physical examination.
• Imaging or ultrasound does not add any benefit to differentiating between palpable and non-palpable testes.¹
• Examination should take place while the child is supine and in a cross-legged position and cover the following steps:¹
  1. Perform a visual examination of the scrotum.
  2. Inhibit the cremasteric reflex with one hand above the symphysis in the groin region before touching the scrotum.
  3. '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.
  4. 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 (e.g. touching the inner thigh).
  5. Look at the femoral, penile and perineal region for ectopic testes.
  6. Diagnostic laparoscopy is the only way to confirm or rule out an intra-abdominal, inguinal or absent/vanishing testis (non-palpable testis). However, an examination under anaesthetic should be carried out before laparoscopy as a previously non-palpable testis may become palpable.

• Prader-Willi syndrome
• Kallmann's syndrome
• Laurence-Moon-Biedl syndrome
• Intersexuality/Congenital adrenal hyperplasia
• Prune belly syndrome

• If by age 1 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).
• Treatment should be completed by 12-18 months of age.¹

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%.^11,12
• Medical treatment may also be useful before or after surgery and may have an beneficial effect on later fertility.¹
• Side effects of hCG treatment can include enlargement of the penis, pubic hair growth, increased testicular size and aggressive behaviour during treatment.¹³

Surgical treatment

• If the testis is palpable: an inguinal approach is used. Orchidopexy or orchidofuniculolysis can be performed.¹ Success rates are up to 92%.¹⁴ 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.
• If the testis is non-palpable: examination under anaesthetic may reveal the previously non-palpable testis. If not, inguinal surgical exploration ± laparoscopy is needed.¹ Every attempt should be made to locate the non-palpable testis. It is likely that the testis will be found just through the inguinal incision but laparoscopy may be needed to search the abdomen. Removal, orchidolysis or orchidopexy can then be performed laparoscopically.

• Increased risk of testicular torsion. This may be associated with the development of a testicular tumour. Torsion of an intra-abdominal testis may present as an acute abdomen.¹⁵
• Increased risk of testicular trauma.

Effect on fertility

• Boys with one undescended testis have a lower fertility rate but the same paternity rate as boys with bilateral descended testes.¹
• Boys with bilateral undescended testes have lower fertility and paternity rates.¹

Risk of testicular malignancy

• There is a 20 x increased risk of developing testicular malignancy in boys with an undescended testis. This is not reduced once treatment for the undescended testis has been carried out.¹
• However, a recent study and a meta-analysis have shown that pre-pubertal orchidopexy for cryptorchidism may be associated with a lower risk of testicular cancer.^16,17
• Orchidopexy facilitates testicular self-examination.¹⁷

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.

The 'National Screening Committee Policy - cryptorchidism screening' agrees that screening for undescended and maldescended testes should take place in the routine physical examination of boys within 72 hours of birth and at the 6-8 week check.¹⁸ Screening is also recommended for boys with a history of undescended testis, during, and after, puberty because of the risk of testicular malignancy.¹