Definition of Varicocele:

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

Causes, incidence, and risk factors:

A varicocele forms when valves inside the veins along the spermatic cord prevent blood from flowing properly. This causes the blood to back up, leading 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. They are more common in men ages 15 - 25 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. This is more common on the left side than the right.