Undescended testes

Undescended testes, or cryptorchidism, the most prevalent congenital abnormality involving male genitalia, is defined as the incomplete descent of one or both testes from the abdomen through the inguinal canal, resulting in the absence of at least 1 testicle from the scrotum.¹

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.

Undescended testes classification²

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.

Palpable:

• True undescended testis: testis lies along the normal path of descent in the abdomen or inguinal region but has never been present in the scrotum.

• Ectopic testis: testis lies outside of the normal path of descent and outside the scrotum, for example, femoral region, perineum, penile shaft, or the opposite hemiscrotum. The most common position is the superficial inguinal pouch. An ectopic testis will not usually descend to the correct position spontaneously.

• Retractile testis: testis has completed the descent into the correct position but may be found above the scrotum along the normal path of descent. The testis can be manipulated easily down to the scrotum and remains there for some time.

Non-palpable:

• True undescended testis (inguinal or intra-abdominal).

• Ectopic testis.

• Absent or atrophic testis: testis may be missing or vanishing (seen in the scrotum at birth but later disappears), causing a non-palpable testis. Potential causes of this are testicular atrophy after intrauterine torsion, or agenesis due to failed development of the testicular blood supply.

Undescended testes may also be classified as:

• Congenital: testis not present from birth.

• Acquired: testis intrascrotal at birth, but subsequently found in an extrascrotal position.

• Ascending testis: testis previously in the scrotum but has then moved to a higher position over time, and no longer lies in the scrotum. May be due to a persisting processus vaginalis (fibrous remnant), which prevents elongation of the testicular vessels and vas deferens, causing secondary ascent of the testis, or may be a complication of inguinal hernia surgery in children.

Epidemiology³

• Undescended testis is the most common birth defect among boys.⁴

• Undescended testes affect 1-6% of males.

• There is a higher incidence in premature babies (up to 30%).

• Unilateral cryptorchidism is four times more likely than bilateral.

• Acquired undescended testes were once considered a sporadic disease. In recent years, reports suggest that they are not uncommon, with an incidence rate about 3 times that of congenital undescended testes.⁵

Aetiology

• The aetiology of cryptorchidism is multifactorial (genetic, maternal and environmental factors).

• However, it occurs most often as an isolated disorder with no obvious cause.

Undescended testes diagnosis²

• This is by physical examination.

• Around 80% of all undescended testes are palpable.

• It can be difficult to distinguish undescended testes from retractile testes.⁴

• 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.

  • 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 (for example, 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.

Syndromes associated with cryptorchidism

• Prader-Willi syndrome.

• Kallmann's syndrome.

• Laurence-Moon syndrome.

• Ambiguous genitalia.

• Congenital adrenal hyperplasia.

• Prune belly syndrome.

Undescended testes treatment and management²

• If, by the age of 6 months, descent has not occurred, spontaneous descent is unlikely. Treatment should be completed by 18 months at the latest as there is potential for histological deterioration and loss of testicular quality after that time which may affect future fertility.

• If there is unilateral undescended testes still present at 3 months then the child should be referred to an appropriate paediatric surgeon, ideally before the age of 6 months.

• The ideal management of cryptorchidism is a highly debated topic within the field of paediatric surgery.

• However, despite early diagnosis in many patients with undescended testes, many are still referred and operated after 1 year of age.³

Medical treatment for undescended testes⁶

• Treatment with human chorionic gonadotrophin (hCG) or gonadotrophin-releasing hormone (GnRH) has been used.

• Hormone therapy has been found to be ineffective and is not recommended for the achievement of testicular descent in unilateral undescended testes.

• There may be a place for endocrine treatment in addition to surgery for some who have bilateral undescended testes or other associated conditions.

Surgical treatment for undescended testes

• 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.⁷

• 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%.⁸ 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.⁹

• 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.¹⁰ Removal, orchidolysis or orchidopexy can then be performed laparoscopically.

Undescended testes complications⁶

• 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.

• Increased risk of testicular cancer.

• Infertility.

• Association with inguinal hernia.

• Increased risk of testicular trauma.

Effect on fertility⁶

• 83% of men with unilateral undescended testis have a normal sperm count, and the paternity rate is up to 89% compared with 94% in the general population.

• The infertility rate may be up to 56% in men with bilateral undescended testes despite surgery, which is six times that of the general population. The paternity rate may be 62%.

Risk of testicular malignancy

• There is a three-fold increase in the incidence of testicular cancer in males with undescended testes.¹¹

• There is a history of cryptorchidism in 5-10% of testicular cancers.

• Prepubertal orchidopexy for cryptorchidism may be associated with a lower risk of testicular cancer than uncorrected cryptorchidism but still higher than the baseline risk for men with fully-descended testes.

• Orchidopexy facilitates testicular self-examination.

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.

Prevention of complications⁶

The National Screening Committee Policy - 'cryptorchidism screening' - states 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 six- to eight-week check. A re-check should be carried out at 4-5 months of age if testes have previously been found to be undescended, to assess for spontaneous descent.