Undescended Testis (Cryptorchidism)
What happens under normal conditions?
Normal testicles (testes) arise early in a boy's development. Although they are located initially in the abdominal cavity, they descend or drop into the scrotal area during the latter part of pregnancy, in response to the baby's normal hormones. The testicles in the infant make sperm and the male sex hormone testosterone .The purpose of the scrotum is to allow the testis to be in a cooler environment than the body, because sperm cannot develop at body temperature. During childhood, sperm in the testicles are undergoing a maturation process that ultimately results in mature sperm at puberty. If the testicles are undescended, meaning not in the scrotum, then the sperm do not mature. The longer this lasts, the lower the chances that the sperm in the affected testicle will mature normally.
What are undescended testicles and how are they diagnosed?
In children with an undescended testicle (testis), the testicle fails to reach the normal position in the scrotum. This condition is obvious on routine examination in the infant and is present in about 3-4% of newborns (and up to 21% of premature newborns). Fortunately, about half of these testicles will descend spontaneously during the first three months of life. Testicles will not descend spontaneously after three months of age. Consequently, about 1% to 2% of boys will need treatment. It is important not to confuse undescended testicles with "retractile" testicles. After six months of age, normal babies and male children have a reflex that pulls the testicles up to protect them when he is cold or frightened. These testicles are in the scrotum at other times and do not require any treatment. An expert physical examination may be needed to distinguish these, and it is important, as only truly undescended testicles need treatment.
The testicles need to be at a temperature that is two to three degrees lower than normal body temperature to produce sperm normally. Fortunately, the scrotum is several degrees cooler than body temperature and hence is the ideal location for the testicle. Testicles that do not descend into the scrotum will not function normally. Because they may not make sperm, they can be a cause of infertility, especially when both testicles are affected. They are also associated with a higher risk of testicular cancer in adulthood (although the risk is still less than one in 100). Many times there is also an associated hernia when the testicles fail to descend normally.
What causes undescended testicles?
In most children with this condition it is not known why the testicles fail to descend. It may be because the testicles are not normal to start with. In other cases there is a mechanical problem that leads them to descend or drop but miss the scrotum, and end up adjacent to the scrotum (these are called "ectopic testicles"). Or, it may be that the infant's hormones may be insufficient to stimulate the testicles normally. It is important, however, to realize that there are no studies showing that the problem is caused by anything that the mother did or ate during pregnancy.
What if the testicle cannot be felt on physical examination?
A testicle that cannot be felt on physical examination is called "nonpalpable". Nonpalpable testicles may be located in the abdomen, absent or atrophic (very small). It is important to determine which of these is true because a testicle left inside the abdomen could form a tumor later in life. Such a tumor may go undetected until it becomes quite large or causes symptoms. Unfortunately, there is no radiologic study, such as an ultrasound, that can definitively determine whether a testicle is present, so this situation always requires surgery. Most surgeons use a technique called laparoscopy. They will find one of three situations: 1) blind ending testicular blood vessels suggesting an absent testicle; 2) vessels exiting the abdomen, proving that there is no testicle within the abdominal cavity; or 3) a testicle in the abdomen. If a testicle is found, it is brought down into the scrotum or removed, depending on its condition and location.
What treatment(s) are available?
Treatment is recommended anytime after six months of age. The time between six and 18 months of age is generally considered best, when taking into account surgical and anesthetic factors. Medical or hormonal treatment is not indicated. In addition, the testis will not descend spontaneously after 3 months of age. Consequently, the only available treatment option is surgery. This operation is called an orchiopexy. It requires general anesthesia, but the baby can almost always go home the same day and usually acts entirely normal within one to two days. An incision about an inch long is made in the groin area (usually it can hardly be seen later). The testicle is separated from all surrounding tissues (and if there is a hernia, this is fixed at the same time) so that it comes easily into the scrotum where it is stitched into place. In some cases, the testicle is too high for this simple operation and more complex procedures (and sometimes even two operations) are needed. Overall, the success rate with surgery is 98%.
What can be expected after treatment?
After treatment, the testicle usually develops to normal size in the scrotum. However, in some cases the testicle is abnormal to start with and never grows properly. In other cases, even though it is of normal size, sperm never develop. In most cases of an undescended testicle on one side, the chances of ultimately fathering a child are very high — virtually the same as normal. It is recommended that, as a teenager, these patients have regular physical examinations and be reminded to perform monthly testicular self-examination because of the slight risk of testicular cancer, which can occur even after successful surgery.
Is an undescended testicle always diagnosed in babies?
No. Increasingly, many boys are being diagnosed with an undescended testicle later in childhood, often between 6 and 10 years of age. These boys had normally descended testicles as infants. This condition is called an “ascending testicle”. The cause is uncertain. However, most think that the spermatic cord does not grow normally as the child grows, and gradually the testis becomes undescended. Often these boys are known to have a retractile testis before the diagnosis of an ascending testicle is made. These testicles need surgical treatment to move the testicle into the scrotum, because sperm maturation will not occur if the testicle remains undescended. For these reasons, it is important that boys undergo genital examination during their annual well child visits to the pediatrician or family physician.
Reviewed: January 2011
Last updated: March 2013
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