What is an undescended testicle (UDT)?
An undescended testicle, also known as cryptorchidism, is when a child’s testicle has not made its way down into the scrotum but stopped somewhere along the way. UDT is the most common congenital abnormality of the genitourinary tract.
Most baby boys will have both testicles in the scrotum at birth. Occasionally, one or both testicles will not have descended within the scrotum at birth. The newborn incidence of UDT is 3-5% (15% of which are bilateral). Newborns who were born premature and have a low birth weight are at a higher risk. Within this population of premature infants, 10% will have UDT, whereas only 3% of full-term baby boys experience this.
Of those children with UDT, 20% of them will have a nonpalpable testicle, meaning it cannot be found on physical exam. Of these children with nonpalpable UDT, 25% will end up with an absent testicle.
By 6 months of age, we expect most of these to resolve on their own without medical intervention. However, 1% will still have undescended testicles that will require surgery. The cause of this is still unknown and several theories exist to explain this condition.
How do you know if your child has UDT?
After your child is born, gently feel the scrotum on both sides and look for a small “ball” on either side. If you are unable to locate them in the scrotum, call your pediatrician to have your baby examined and to rule out an UDT. The picture above shows the tract the testicle follows as it descends into the scrotum. It also shows the different locations where it might stop leading to an UDT.
Types of UDT:
- Retractile testes: These are normal testis that will rise up in the suprascrotal position in the inguinal canal due to the cremasteric reflex. This superficial reflex causes the muscle on the spermatic cord to contract when the boy is cold, anxious, or if the inner thigh is stroked. The testicle is palpable and returns to the normal scrotal position when the child is relaxed. No surgical correction is required.
- Ectopic testes (<5% of cases): This is a testicle that descended correctly but was then misdirected beyond the external inguinal ring. In these cases, the testicle is found in other areas.
- Incompletely descended testes (95% of cases): The testicle does not descend fully along the tract and therefore can be found intraabdominally, in the inguinal canal or even the external ring:
- Palpable (80%): The testicle is found during the exam in either the prepubic or inguinal canal
- Nonpalpable (15%): During the exam, the testicle is not found, typically located in the abdomen or is absent
- Absent or atrophic testes (3.3% of all cases)
If left as is, the undescended testicle can lead to some problems in the future including:
- Testicular cancer: A child who remains with an UDT is at a higher risk of testicular cancer. As your boy grows up, he is less likely to become aware of testicular cancer as the testicle is not palpable in the scrotum. Eleven percent of testicular cancer originates from UDT. The increased risk is 25-30 times for these patients. Of patients with UDT, 1 in 100 will develop testicular cancer.
- Risks of infertility: This becomes a problem when a child has both testicles undescended, which results in a paternity rate (the ability to father a child naturally) of 62%. If a child has only one UDT, the paternity rate is similar to a child with both testicles descended.
- Inguinal hernia: Most congenital undescended testicles (about 90%) will present with an inguinal hernia.
- Testicular torsion: This is 10 times more like to occur in a patient with undescended testicles.
- Testicular trauma: Your child is more likely to get injured with trauma to the area as it compresses against the pubic bone.
How to diagnose:
UDT is typically diagnosed in clinic with a good physical exam. Your medical provider will gently examine the scrotum in order to find the testes. If they are not found within the scrotum, your child’s provider will examine above the scrotum and will slowly work their way down to the scrotum while applying a gentle downward pressure.
Imaging to find the testicle is not typically done since it tends to yield false-positive or false-negative results. In the case of nonpalpable testes, a scrotal ultrasound can be done, but surgery is still necessary, therefore imaging is typically not needed.
Now let’s fix this! Surgery is the only way to correct this. We aim to operate as soon as possible, after 6 months of age. Over 6 months of age, it is very unlikely that the testicle will spontaneously descend.
For palpable testicles, the surgeon will make a small incision in the groin on the affected side, then locate the testicle and free it up from the surrounding tissue that is keeping it tethered.
If a hernia is present, it will be corrected at that time. The testes will then be brought down and placed into the scrotum through a second opening. The testicle will then be anchored with a stitch. The success rate is 99% and most of these surgeries are outpatient.
Nonpalpable testicles need to first be found through laparoscopic exploration. This is done in the operating room under general anesthesia. A camera will be inserted into the abdomen through a small opening. Once the testicle is identified, it will then be placed in the scrotum in 1 or 2 stages. If an abnormal or too small testicle is identified, it may be removed as it is not likely to function normally. If no testicle is identified, the procedure is concluded.
Retractile testicles do not require medical intervention.
- Baskin L.S., Kogan B.A. Handbook of Pediatric Urology. Second Edition. A Lippincott Williams & Wikins Handbook. 2005.
- Cooper C.S., Docimo S.G. Undescended Testes (cryptorchidism) in children: Management. UpToDate. Sept 24, 2018. https://www.uptodate.com/contents/undescended-testes-cryptorchidism-in-c...