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Undescended testes

Maldescended and retractile testes

Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find one of our health articles more useful.

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.

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Undescended testes classification

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 testes or testis.

  • The ascending testis syndrome.

  • Testicular maldescent.

Retractile testes1

  • 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.

The ascending testis syndrome

  • Previously normal or retractile testes can become high with a shortened spermatic cord that prevents the testis from staying in the scrotum.

  • It is a rare condition which occurs more commonly on the left side2 .

  • It is usually diagnosed in those aged 8-10 years.

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 age3 .

  • 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.

An alternative classification system advocated by the European Association of Urology (EAU) is4 :

  • Undescended testis:

    • Palpable:

      • Inguinal

      • Ectopic

      • Retractile

    • Non-palpable:

      • Inguinal

      • Ectopic

      • Intra-abdominal

      • Absent:

        • Agenesis

        • Vanishing testis


  • Undescended testis is the most common birth defect among boys3 .

  • 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.

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  • 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 diagnosis4

  • This is by physical examination.

  • Around 70% of all undescended testes are palpable.

  • It can be difficult to distinguish undescended testes from retractile testes3 .

  • 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 (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.

Important information

Guidelines from the European Association of Urology (EAU)4

The EAU's Paediatric Urology guidelines suggest that undescended and maldescended testes should be categorised into palpable and non-palpable testes, as the location and existence of the testis affects clinical management.

Bilateral, non-palpable testes and any suggestion of sexual differentiation problems (eg, hypospadias) require urgent, mandatory endocrinological and genetic evaluation.

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Syndromes associated with cryptorchidism

Undescended testes treatment and management4

  • 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 months6 .

  • 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 age5 .

Medical treatment for undescended testes6

  • 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 but the evidence is weak .

  • 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 opposite7 . Studies have shown that hCG treatment may decrease sperm counts together wtih the future fertility potential8 .

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 life9 .

  • 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%10 . 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 cancer11 .

  • 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 urologists12 . Removal, orchidolysis or orchidopexy can then be performed laparoscopically.

Undescended testes complications

  • 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 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 testes13 .

  • 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.

  • 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.

Further reading and references

  1. Keys C, Heloury Y; Retractile testes: a review of the current literature. J Pediatr Urol. 2012 Feb;8(1):2-6. doi: 10.1016/j.jpurol.2011.03.016. Epub 2011 Apr 16.
  2. Yoshida T, Ohno K, Morotomi Y, et al; Clinical and pathological features of ascending testis. Osaka City Med J. 2009 Dec;55(2):81-7.
  3. Snodgrass W, Bush N, Holzer M, et al; Current referral patterns and means to improve accuracy in diagnosis of undescended testis. Pediatrics. 2011 Feb;127(2):e382-8. doi: 10.1542/peds.2010-1719. Epub 2011 Jan 24.
  4. EAU Paediatric Urology Guidelines. Edn. presented at the EAU Annual Congress Copenhagen; European Association of Urology, 2018 - updated 2023
  5. Nah SA, Yeo CS, How GY, et al; Undescended testis: 513 patients' characteristics, age at orchidopexy and patterns of referral. Arch Dis Child. 2014 May;99(5):401-6. doi: 10.1136/archdischild-2013-305225. Epub 2013 Nov 13.
  6. Undescended testes; NICE CKS, February 2020 (UK access only)
  7. Yilmaz O, Akyol I, Ozyurt M, et al; The influence of hormonal treatment with beta-human chorionic gonadotropin for cryptorchidism on future fertility in rats. J Pediatr Urol. 2015 Apr;11(2):92.e1-4. doi: 10.1016/j.jpurol.2014.12.011. Epub 2015 Mar 10.
  8. Abaci A, Catli G, Anik A, et al; Epidemiology, classification and management of undescended testes: does medication have value in its treatment? J Clin Res Pediatr Endocrinol. 2013;5(2):65-72. doi: 10.4274/Jcrpe.883.
  9. Chan E, Wayne C, Nasr A; Ideal timing of orchiopexy: a systematic review. Pediatr Surg Int. 2014 Jan;30(1):87-97.
  10. Thomas RJ, Holland AJ; Surgical approach to the palpable undescended testis. Pediatr Surg Int. 2014 Jul;30(7):707-13. doi: 10.1007/s00383-014-3518-6. Epub 2014 May 29.
  11. Cobellis G, Noviello C, Nino F, et al; Spermatogenesis and cryptorchidism. Front Endocrinol (Lausanne). 2014 May 1;5:63. doi: 10.3389/fendo.2014.00063. eCollection 2014.
  12. Fine RG, Franco I; Laparoscopic orchiopexy and varicocelectomy: is there really an advantage? Urol Clin North Am. 2015 Feb;42(1):19-29. doi: 10.1016/j.ucl.2014.09.003. Epub 2014 Nov 20.
  13. Haire AR, Flavill J, Groom WD, et al; Unidentified undescended testes in teenage boys with severe learning disabilities. Arch Dis Child. 2015 May;100(5):479-80. doi: 10.1136/archdischild-2014-307155. Epub 2015 Feb 2.

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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