A retractile testicle is a testicle that may move back and forth between the scrotum and the groin. When the retractile testicle is residing in the groin, it might be easily guided by hand into its proper position in the scrotum — the bag of skin hanging behind the penis — during a physical exam.
For most boys, the problem of a retractile testicle goes away sometime before or during puberty. The testicle moves to its correct location in the scrotum and stays there permanently.
In fewer than 5 percent of cases, the retractile testicle remains in the groin and is no longer movable. When this happens, the condition is called an ascending testicle or an acquired undescended testicle.
Testicles form in the abdomen during fetal development. During the final months of development, the testicles gradually descend into the scrotum. If this descent isn't completed at birth, the testicle usually descends within a few months. If your son has a retractile testicle, the testicle originally descended as it should, but doesn't remain in place.
Signs and symptoms of a retractile testicle include:
- The testicle may be moved by hand from the groin into the scrotum and won't immediately retreat to the groin.
- The testicle might spontaneously appear in the scrotum and remain there for a time.
- The testicle might spontaneously disappear again for a time.
The movement of a retractile testicle almost always occurs without pain or discomfort. As a result, it's noticed only when the testicle is no longer seen or felt in the scrotum.
The position of one testicle is usually independent of the position of the other one. For example, a boy might have one normal testicle and one retractile testicle.
Retractile testicle is different from undescended testicle (cryptorchidism). An undescended testicle is one that never entered the scrotum.
When to see a doctor
During regular well-baby checkups and annual childhood checkups, your son's doctor will examine your son's testicles to determine if they're descended and appropriately developed. If you believe that your son has a retractile or ascending testicle — or have other concerns about the development of his testicles — see his doctor. He or she will tell you how often to schedule checkups to monitor changes in the condition.
If your son experiences pain in the groin or testicles, see your son's doctor immediately.
An overactive muscle causes a testicle to become a retractile testicle. The cremaster muscle is a thin pouch-like muscle in which a testicle rests. When the cremaster muscle contracts, it pulls the testicle up toward the body.
The main purpose of the cremaster muscle is to control the temperature of the testicle. In order for a testicle to develop and function properly, it needs to be slightly cooler than normal body temperature. When the environment is warm, the cremaster muscle is relaxed; when the environment is cold, the muscle contracts and draws the testicle toward the warmth of the body. The cremaster reflex can also be stimulated by rubbing the genitofemoral nerve on the inner thigh and by extreme emotion, such as anxiety.
If the cremaster reflex is strong enough, it can result in a retractile testicle, pulling the testicle out of the scrotum and up into the groin.
Causes of an ascending testicle
Some retractile testicles can become ascending testicles. This means the once-movable testicle becomes stuck in the "up position." Contributing factors can include:
- Short spermatic cord. Each testicle is attached to the end of the spermatic cord, which extends down from the groin and into the scrotum. The cord houses blood vessels, nerves and the tube that carries semen from the testicle to the penis. If growth of the spermatic cord doesn't keep pace with other body growth, the relatively short cord might pull the testicle up.
- Remnants of fetal tissues. Abnormal remnants of fetal tissues that created the path for normal testicular descent might affect the growth or elasticity of the spermatic cord.
- Scar tissue from hernia surgery. An inguinal hernia is caused by a small gap in the abdominal lining through which a portion of the intestines can protrude into the groin. Scar tissue following surgery to repair the hernia might limit the growth or elasticity of the spermatic cord.
Retractile testicles are generally not associated with complications, aside from a greater risk of the testicle becoming an ascending testicle.
An ascending testicle, if not treated, is vulnerable to the same risks associated with an undescended testicle. Surgical treatment during childhood to correct an undescended testicle reduces these risks. Risks associated with an untreated undescended testicle include:
- Testicular cancer. Testicular cancer usually begins in the cells in the testicle that produce immature sperm. What causes these cells to develop into cancer is unknown. Men who have had an undescended testicle have a greater risk of testicular cancer.
- Fertility problems. Low sperm counts, poor sperm quality and low fertility rates are more likely among men who have had an undescended testicle.
- Testicular torsion. Testicular torsion is the twisting of the spermatic cord. This painful condition cuts off blood to the testicle. If not treated promptly, it might result in the loss of the testicle. An undescended testicle increases the risk of testicular torsion.
- Trauma. A testicle located in the groin might be susceptible to trauma or injury from compression against the pubic bone.
Sept. 16, 2015