Varicoceles are a relatively common condition (affecting approximately 10 percent of men) that tends to occur in young men, usually during the second or third decade of life. Sometimes, these varicoceles cause no symptoms and are harmless. But sometimes a varicocele causes pain or atrophy (shrinkage), or fertility problems.

Normally, blood flows to the testicles through an artery, and flows out via a network of tiny veins that drain into a long vein that goes up through the abdomen. The direction of blood flow in this vein should always be up, toward the heart. A series of one-way valves in the vein prevent the reverse flow of blood back to the testicles.

What Causes Varicoceles ?

These one-way valves sometimes fail. The reverse flow of blood stretches and enlarges the tiny veins around the testicle to cause a varicocele, a tangled network of blood vessels, or varicose veins (see Figure 1).