What is a varicocele?

All boys have veins in the scrotum that take blood from the testicles up towards the heart. The blood that is slow to return to the heart can collect in the veins, which then causes the veins to get bigger, or become swollen. When this happens in the scrotum it is called a varicocele.

Varicocele Illustration

Although they don't happen to every boy, varicoceles are fairly common. About 17 percent of boys between the ages of 13-25 years old have varicoceles. More than 90 percent of the time, they appear on the left testicle and they mostly occur during or after puberty. That's because during puberty, the testicles grow rapidly and need more blood delivered to them. Although most of the blood continues to flow correctly, blood can begin to back up, creating a varicocele.

Signs and symptoms

In most cases, boys have no symptoms at all and might not even know they have a varicocele. Usually, a varicocele is noticed by a doctor during a testicular exam.

The veins will feel like a “bag of worms” while your child is standing and may disappear while he is lying down.

Sometimes after heavy exercise, hot weather, or standing for a long time, your child may feel a heaviness or dull discomfort in his scrotum.

Testing and diagnosis

At the Division of Urology, your child's urologist will order a scrotal ultrasound, a painless test that will take pictures and measure the size of each testicle. We will compare the size of the left and right testicle to make sure they are equal. As your child continues to go through puberty and adolescence, we will order additional ultrasounds to make sure the testicles continue to grow equally.


Surgery is only indicated when a size difference between the left and right testicles is larger than 20 percent, based on several ultrasounds.

Once your child reaches 18 years old, we will offer the option of a semen analysis. If sperm count is low on repeated specimens, surgery may be indicated.

Through continued research at CHOP, we have shown that as boys go through puberty, the testicles may grow at different rates. If a size discrepancy is evident, we will ask that the ultrasound be repeated before deciding to go through with surgery.

Reviewed by: Division of Urology

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