Clinical Notes : Paediatrics

6. Undescended Testes

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Maldescended testis

  • any abnormality in testicular descent that is not a normal variant, and includes the conditions defined below. (1)


Undescended testis

  • undescended testis (UDT) is the second most common paediatric surgical condition after inguinal hernias.(2)

  • a testis that is not in the scrotum by the age of three months because of a failure of normal descent.

  • 5% of boys have a UDT at birth, 1–2% at three months 1% at one year; hence, it is uncommon for testes to descend after three months.(3)


Ectopic testis

  • an ectopic testis has deviated from the normal path of testicular descent (from the abdomen through the inguinal canal and into the scrotum) and may be found in almost any other region.


Ascending testis

  • an ascending or acquired testis may have descended previously but then moved to a higher position over time because of an abnormally persisting fibrotic remnant of the processus vaginalis (an outpouching of peritoneum that follows the testis as it descends into the scrotum from the abdomen).

  • the remnant usually regresses in the first few years but can continue causing testicular ascent.(4)

  • regular re-examination is recommended in a primary care setting even if the testes were previously noted in the scrotum 


Impalpable testis

  • 30% of testes not palpable in the scrotum (impalpable) are found in the inguinal region; 20% are intra-abdominal and 10% are in an ectopic location.(2) 

    • an impalpable testis may be absent in approximately 40% of boys as part of a testicular regression syndrome.

    • this is usually secondary to intrauterine or perinatal torsion prior to fixation of the testis in the scrotum, and a testicular ‘nubbin’ or abnormal testicular remnant is the only tissue present.(6)

    • hypertrophy of the contralateral testis is likely to occur.

  • a useful comparison for the appropriate size of the testis is the size of the glans penis.(4)


Retractile testis

  • A retractile testis can be brought all the way into the scrotum without tension but retracts back to an inguinal position after a variable period

  • It is a normal variant.

  • The cremaster muscle contracts to control the temperature of the testis, retracting it to the body when environmental temperature changes.

    • When androgen levels are high at birth and at 3–6 months, the cremaster muscle is more relaxed.

    • When androgen levels decrease after this, the muscle has a greater tendency to contract, causing retractile testes.(4)

Clinical examination for a possible undescended testicle

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A. Inspect the scrotum, note any scrotal hypoplasia and whether it appears.

B. Occlude the external inguinal rings with digital pressure as this prevents retraction of the testicles with a cremasteric response.

C. Palpate the normal-in-appearance hemi-scrotum.

D. Palpate the hypoplastic hemi‑scrotum.

E. Milk from the external ring to the scrotum to attempt to palpate the testicle.
F. Once located, assess whether the testicle can be moved to the scrotum.

Normal physiology of testicular descent

There are two stages of testicular descent, which occur at 8–15 and 25–35 weeks of gestation.(4) 

  • The first stage is enlargement of the gubernaculum.

    • If the first stage fails, the testis remains intra-abdominal

  • The second stage involves the gubernaculum extending into the scrotum, travelling approximately five centimetres, so the testis becomes intrascrotal.

    • This stage is more commonly disrupted as it is more complex, leading to localisation of the testis between the deep inguinal ring and the scrotum.

Emerging evidence suggests that UDT represents a disruption in the hormonally controlled testicular descent in fetal life and is probably secondary to a disturbance of intrauterine hormonal function (3)

Important risk factors identified include

  • maternal smoking

  • family history of UDT

  • low birth weight

  • prematurity.

  • the prevalence in premature boys is up to 30.1%. (7)

The majority of other posited risk factors have not been supported with consistent evidence, including :

  • maternal diet and caffeine consumption

  • intrauterine exposure to high levels of oestrogen

  • maternal use of medication

  • assisted reproduction



  • Ask parents if the testis has ever been in the scrotum.

    • Retractile testes often descend during a warm bath.

    • An ectopic testis may appear as a lump in a different location.

  • Ideally, the physical examination should be done in a a warm environment and when the child is calm.

    • A significant suprapubic fat pad can influence the examination and make a UDT difficult to detect.

    • A well-developed hemiscrotum usually indicates an ascending or retractile testis.

    • An undeveloped (hypoplastic) appearance indicates a possible UDT

    • It is important to recall that a UDT is often mobile as it remains within a patent processus vaginalis.

  • Classify the testis as normal, high scrotal, supra-scrotal or impalpable

    • Ectopic testes can be in the perineum, femoral region, pre-penile region and even the opposite hemiscrotum.(8)


Possible anatomical positions of an undescended testicle

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Current guidelines recommend referral at 3–6 months for unilateral UDT, and orchidopexy between six and 12 months (9)


When an ascending testis is detected during childhood, the optimum time for orchidopexy is before puberty (usually around 7–8 years.

If a testis appears to be ‘high’ (at the neck of the scrotum), the child needs yearly review as the testis may ascend.

If a testicular nubbin is found, there is some controversy around mandatory removal because of a potential risk of malignancy.

  • There is insufficient evidence to suggest an inguinal or scrotal nubbin requires routine excision, as potentially malignant cells fail to persist as the child ages.

  • Intra-abdominal nubbins may contain more elements and warrant excision.

Investigation and treatment for undescended testicles in a newborn male infant

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  • with bilateral UDT (10)

    • despite orchidopexy, the infertility rate may be up to 56%, six times that of the general population

    • the paternity rate (the percentage of men attempting who successfully achieve conception) may be 62%

  • with unilateral UDT (11)

    • 83% have a normal sperm count

    • the paternity rate is up to 89%

  • Comparatively, the non-cryptorchid population has a paternity rate of 94%


  • 2% in UDT

    • although this is four to five times the risk in the general population, parents can be reassured this is still relatively low (12)

  • the risk of cancer is usually highest in those with intra-abdominal testes

  • the tumours usually develop in young adults as germ cells rapidly multiply after puberty.(13)


1. Undescended testes: What general practitioners need to know

Evie Yeap    Ramesh M Nataraja    Maurizio Pacilli  

Volume 48, No. 1–2, January–February 2019


2. Hutson JM, O’Brien M, Beasley SW, Teague WJ, King SK

Jones’ clinical paediatric surgery.

7th edn. Chichester, England: Wiley, 2015; p. 332

3. Gurney JK, McGlynn KA, Stanley J, et al.

Risk factors for cryptorchidism. Nat Rev Urol 2017;14(9):534–48.


3. Hutson JM, Vikraman J, Li R, Thorup J.

Undescended testis: What paediatricians need to know. J Paediatr Child Health 2017;53(11):1101–04.


5. Nataraja RM, Yeap E, Healy CJ, et al.

Presence of viable germ cells in testicular regression syndrome remnants: Is routine excision indicated? A systematic review.

Pediatr Surg Int 2018;34(3):353–61. 


6. Vikraman J, Donath S, Hutson JM.

Undescended testes: Diagnosis and timely treatment in Australia (1995–2014).

Aust Fam Physician 2017;46(3):152–58


7. Casanova NC, Johnson EK, Bowen DK, et al.

Two-step Fowler-Stephens orchiopexy for intra-abdominal testes: A 28-year single institution experience.

J Urol 2013;190(4):1371–76. 


8. Teague WJ, King SK.

Paediatric surgery for the busy GP – Getting the referral right.

Aust Fam Physician 2015;44(12):890–94


9. Kolon TF, Herndon CD, Baker LA, et al.

Evaluation and treatment of cryptorchidism: AUA guideline.

J Urol 2014;192(2):337–45. 


10. Goel P, Rawat JD, Wakhlu A, Kureel SN.

Undescended testicle: An update on fertility in cryptorchid men.

Indian J Med Res 2015;141(2):163–71


11. Lee PA, O'Leary LA, Songer NJ, Coughlin MT, Bellinger MF, LaPorte RE.

Paternity after bilateral cryptorchidism. A controlled study.

Arch Pediatr Adolesc Med 1997;151(3):260–63


12. Cortes D, Thorup JM, Visfeldt J.

Cryptorchidism: Aspects of fertility and neoplasms. A study including data of 1,335 consecutive boys who underwent testicular biopsy simultaneously with surgery for cryptorchidism.

Horm Res 2001;55(1):21–7


13. Virtanen HE, Bjerknes R, Cortes D, et al.

Cryptorchidism: Classification, prevalence and long-term consequences.

Acta Paediatr 2007;96(5):611–16


Guidelines on paediatric urology

European Association of Urology



Diagnosis, management, and followup of cryptorchidism

Canadian Urological Association-Pediatric Urologists of Canada



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