A varicocele is a widening of the veins along the spermatic cord. This cord holds up a man's testicles .

A varicocele forms when valves inside the veins along the spermatic cord prevent blood from flowing properly. This causes the blood to backup, which leads to swelling and widening of the veins. (This is essentially the same process that leads to varicose veins, which are common in the legs.)

Varicoceles usually develop slowly, and may not cause symptoms. They are more common in men between 15 and 25 years old and are most often seen on the left side of the scrotum. Varicoceles are often the cause of infertility in men.

The sudden appearance of a varicocele in an older man may be caused by a kidney tumor, which can block blood flow to a vein.

• Visible, enlarged, twisted veins in the scrotum
• Infertility
• A painless testicle lump, scrotal swelling, or bulge within the scrotum

The health care provider will examine the groin area, including the scrotum and testicles. The doctor may be able to feel a non-tender, twisted mass along the spermatic cord. (It feels like a bag of worms.)

However, the mass may not be able to be seen or felt, especially when lying down.

The testicle on the side of the varicocele may be smaller than the one on the other side.