A boy’s testes normally begin life up in the abdomen, as do ovaries. Before birth, they normally descend through a flexible tube, called the inguinal canal, and end up in the scrotum.
The testes usually make their journey from within the abdomen down into the scrotum at around 32 to 36 weeks’ gestation. Sometimes, one or both testes do not make this journey by the time a boy is born.
Most of the time, an undescended testicle remains in the inguinal canal, and can be felt under the skin up above the scrotum. Sometimes the testicle remains in the abdomen and sometimes it is absent altogether.
Less commonly, if both “testes” remain in the abdomen, they may actually be ovaries. Sometimes what appears to be a boy is actually a girl with congenital adrenal hyperplasia. There are several other disorders of sex hormone production that result in ambiguous genitalia, and may include undescended or absent testes.
Acquired undescended testicle is the name given when testes are found in the scrotum at birth, but as the boy grows, one or both appears to move back upwards. This is usually found in preschool or school-age boys, and is thought to result from the spermatic cord (the cord that the testicles hang from) not growing as rapidly as the rest of the body.
If untreated, undescended testicles can lead to future infertility and/or testicular cancer. They are also associated with inguinal hernias in which part of the intestines travel down the still-open inguinal canal. There is some evidence that boys with an undescended testis/testes are at higher lifetime risk of developing male breast cancer.
Retractile testes are those that are in the scrotum some of the time, but then spring up out of the scrotum from time to time. A normal reflex in healthy boys pulls the testes up close to the body when protection or warmth is needed. In some boys, this reflex is particularly strong. Retractile testes are not thought to be at higher risk for infertility or cancer.
Undescended testicles can occur in any boy, but they are far more common among those who are born early. Sometimes they occur as a complication of hernia repair surgery.
Undescended testicles appear to be getting more common.
Undescended testicle is suspected when the testis is not easily identified in the scrotum. The testes are easiest to find when the boy is relaxed and warm with the knees flopped apart–as in a warm bath.
Sometimes the scrotum is smaller and less developed on the side of the undescended testicle, with fewer folds and wrinkles.
Most undescended testicles descend on their own in the first three months. Many more will descend during the next three months. Those that are still undescended in six months generally require treatment.
The testicles themselves usually remain normal during the first six months, whatever their location, but after about six months the cells in the testicles gradually begin to change.
The initial diagnosis of undescended testicle is made on physical exam. If the testis is not located, an imaging study, such as an ultrasound, or surgery is needed to locate the testicle.
The usual treatment of undescended testicle is surgery, often performed by a pediatric urologist, to bring the testicle into the scrotum and attach it there. This is usually outpatient surgery, with a very high success rate. It is performed at the earliest appropriate age.
Occasionally hormone treatment is used in an attempt to trigger the testicle’s journey to continue into the scrotum.
Prevention is often not possible. Preventing preterm delivery is the best way to prevent undescended testicles. This would include obtaining good prenatal care and avoiding exposures (such as tobacco smoke, infections, or drugs) that might trigger early labor.
Cryptorchidism, Retractile testicle, Acquired undescended testicle