RELATED STORIES • Swollen testicle: A cause for concern?

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A varicocele is an enlargement of the veins within the scrotum, the loose bag of skin that holds the testicles. A varicocele is similar to a varicose vein of the leg.

Up to one in five men have a varicocele. For males who are infertile, the figure is higher — about 40 percent. Varicoceles are the most common cause of low sperm production and decreased sperm quality, although not all varicoceles affect sperm production.

Most varicoceles develop over time. They usually occur in the left testicle, most likely because of the position of the left testicular vein. However, a varicocele in one testicle can affect sperm production in both testicles. Fortunately, most varicoceles are easy to diagnose and, if they cause symptoms, can be repaired surgically.

A varicocele usually produces no symptoms. Rarely, it may cause pain that may worsen over the course of a day because of physical exertion and typically is relieved by lying on your back. Varicoceles can grow larger and become more noticeable over time.

The spermatic cord, which supplies blood to and returns blood from the testicle, houses the vas deferens, which carries sperm from the testicles. The pampiniform plexus is a group of veins within the scrotum and above the testicles. The pampiniform plexus drain blood from the testicles. Enlargement of these veins often occurs during puberty.

It's not certain what causes varicoceles, but many experts believe abnormal valves within the veins prevent normal blood flow. The resulting backup causes the veins to widen (dilate).

You're at greater risk for varicoceles between the ages of 15 and 25.

Because of the lack of symptoms, a varicocele often is discovered during an evaluation of fertility or during a routine physical exam. However, if you experience pain or swelling in your scrotum, contact your doctor. A number of conditions can cause testicular pain, and some of the conditions require immediate treatment. Your doctor can determine which condition is causing your pain.

Your doctor will conduct a physical exam, which may reveal a twisted, nontender mass above your testicle. Some people have described the mass as feeling like a bag of worms. If it's large enough, your doctor will be able to feel it while you're standing up. If you have a smaller varicocele, your doctor may ask you to take a deep breath and hold it while you bear down (Valsalva maneuver). This helps your doctor detect abnormal enlargement of the veins.

If the physical exam is inconclusive, your doctor may order a scrotal ultrasound. This test, which uses high-frequency sound waves to create precise images of structures inside your body, may be used to ensure there isn't another reason for your symptoms. One such condition is a tumor that compresses the spermatic vein.

A varicocele may cause :

• Shrinkage of the affected testicle (atrophy). The bulk of the testicle is made up of sperm-producing tubules. When damaged, as from varicocele, the testicle shrinks and softens. It's not clear what causes the testicle to shrink, but experts believe it has to do with the malfunctioning valves, which allow blood to pool in the veins. The result is increased pressure in the veins and exposure to toxins in the blood, which stays in place longer because of the pooling.
• Infertility. It's not clear how varicoceles affect fertility. Some experts believe the testicular veins cool blood in the testicular artery, helping to maintain the proper temperature for optimal sperm production. By blocking venous blood flow, a varicocele may keep the temperature too high, affecting sperm formation and movement (motility).

Varicoceles usually require no treatment. However, if you're infertile or your varicocele causes pain or testicular atrophy, you may want to undergo varicocele repair. Treatment is aimed at sealing off the affected vein to redirect the blood flow into normal veins.

Although varicoceles typically develop in adolescence, it's less clear whether you should have varicocele repair at that time. Indications for repairing a varicocele in adolescence include progressive testicular atrophy, pain or abnormal semen analysis results.

Varicocele repair presents relatively few risks. Increased fluid around the testicles (hydrocele) occurs in a small percent of cases. Recurrence of varicoceles is a risk, affecting perhaps one in 10 men who undergo repair. Repair methods include:

• Open surgery. This most common form of treatment usually is done on an outpatient basis, under general or local anesthetic. The surgeon may approach the vein through your groin (transinguinal), abdomen (retroperitoneal) or below the groin (infrainguinal/infrapubic). Transinguinal surgery is most frequently used.

  Recovery after surgical repair usually proceeds rapidly. Your doctor may advice you to return to normal activities that aren't strenuous after two days. As long as you're not uncomfortable, you can return to more strenuous normal activity, such as exercising, after two weeks. Pain resulting from this surgery usually is mild. Your doctor may prescribe pain medication for the first two days after surgery. After that, your doctor may advise you to take over-the-counter (OTC) painkillers, such as acetaminophen (Tylenol, others) or ibuprofen (Motrin, Advil, others) to relieve discomfort.

  Your doctor may advise you not to have sexual intercourse for one week. It takes about 72 days for sperm to generate, so you'll have to wait three or four months after surgery to get a semen analysis to determine whether the varicocele repair was successful in restoring your fertility.

• Laparoscopic surgery. With this approach, the surgeon makes a small incision in the abdomen and passes a tiny instrument through the incision to see and to repair the varicocele. However, this procedure, which requires general anesthetic, isn't used generally because it poses more risk while offering little advantage.
• Percutaneous embolization. A radiologist inserts a tube into a vein in your groin or neck through which instruments can be passed. Viewing your enlarged veins on a monitor, the doctor releases coils or balloons to create a blockage in the testicular veins, which interrupts the blood flow and repairs the varicocele. This procedure uses sedation and may take several hours. Again, because of presenting greater risks than open surgery and offering little advantage, this procedure isn't widely used.

If you have a varicocele that causes you minor discomfort but doesn't affect your fertility, you might try the following for pain relief:

• Take OTC painkillers, such as acetaminophen (Tylenol, others) or ibuprofen (Motrin, Advil, others).
• Wear an athletic supporter to relieve pressure.