Undescended testes (UDT) are a common finding in the neonatal period. It affects up to one in 20 term males and up to one-third of preterm males. In most cases, the aetiology is unknown.
The UDT may be best classified as palpable or non-palpable. The non-palpable testis is uncommon (less than 10 per cent) with approximately half of these atrophic. The palpable UDT should be defined by the lowest point to which it can be mobilised, with most cases being palpable in the groin.
If a testis is not readily identified, a finger sweep should be performed from the anterior iliac crest along the inguinal canal while palpating the scrotum.
Refer to surgical services if a palpable UDT fails to descend by three months of age or the testis is non-palpable. Exclude the diagnosis of ambiguous genitalia.
Types of undescended testes
- In premature babies the testes may not yet have descended when the baby is born
- Some hormone and genetic disorders may cause undescended testes
- Unknown aetiology
- Undescended testes develops after birth
- Baby born with testes in the scrotum
- As growth occurs the spermatic cord fails to grow at the same rate, ending up short and pulling the testes from the scrotum into the groin.
Increased risk of infertility and malignancy
The risk of infertility and of testicular malignancy is increased in men with a history of UDT. The UDT is also more vulnerable to trauma and torsion. Histologic changes in the uncorrected UDT are seen at approximately 18 months to two years. If at term the testes are normally sited, deep in the scrotum, the infant is unlikely to develop true acquired cryptorchidism.
UDT in association with severe hypospadias must be assessed for congenital adrenal hyperplasia and other causes of ambiguous genitalia. Approximately 25 per cent of neonates with undescended testes and hypospadias have ambiguous genitalia.
An ectopic testis (one that has not followed the normal path of descent) is rare and should be referred for surgical review.
The ectopic testis may be positioned in the lower part of the abdomen, front of thigh, femoral canal, skin of penis or behind the scrotum. The testis is usually developed, and accompanied by an indirect inguinal hernia.
Imaging studies are rarely of use in identifying a non-palpable UDT.
Immediate endocrine referral and further investigations are necessary if undescended testes are associated with ambiguous genitalia.
Failure to descend by approximately three months of age is considered abnormal, and these infants should be referred for surgical opinion. The optimal time for orchidopexy is at about six to 12 months of age. This allows for further spontaneous descent but may reduce some of the sequelae of testicular non-descent.
Although surgery to place the testis in the scrotum may not reduce the risk of infertility or malignancy, it improves the endocrine function of the testis and facilitates testicular self-examination. It also reduces the risk of torsion and direct trauma. Occasionally the testis does not reach the scrotum after the first operation and the procedure needs to be done again.
Surgical exploration (laparoscopy) for the non-palpable testis is warranted as in approximately half of these cases the testis may be salvaged. In the remainder, the testis is absent or a testicular remnant with neoplastic potential may be removed.
Absence of both testes (anorchia) is rare.
- American Academy of Pediatrics (1996) Surgery on the genitalia of male children with particular reference to the risks, benefits, and psychological effects of surgery and anesthesia.
- Avery, G.B., Fletcher, M.A., and MacDonald, M.G. editors. Neonatology: Pathophysiology and Management of the Newborn. 5th edition. Lippincott, Williams & Wilkins. 1999.
- Hutson, J.M., Woodward, A.A., Beasley, S.W. (editors). Jones’ Clinical Paediatric Surgery, Diagnosis and Management. 5th edition. Blackwell Science Asia. 1999.
- Levene, M.I., Tudehope, D.I., and Thearle, M.J. Essentials of Neonatal Medicine. 3rd edition. Blackwell Science. 2000.
- Ashcraft, K.W., Murphy, J.P., Sharp, R.J., Sigalet, D.L., Snyder, C.L. (editors). Pediatric Surgery. 3rd edition. W.B. Saunders Company. 2000.
Get in touch
First published: August 2013
Last reviewed: October 2018
Review by: July 2019
Uncontrolled when downloaded
Page last updated: 23 Nov 2018