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A varicocele is the swelling of the veins inside the scrotum. A varicocele is similar to a varicose vein you might see in your leg except they happen around the testicles.

A varicocele forms when valves inside the veins that run along the spermatic cord stop blood from flowing the right way. Blood backs up, which leads to swelling and enlargement of the veins. Varicoceles are more common on the left side of the scrotum.

About 

of varicocele occur in the United States each year, affecting about 

Most varicoceles do not need to be treated with surgery. Men with varicoceles still have about an 80% chance of being able to have children.

Most varicoceles develop over time. Fortunately, most don't need treatment. 

Most men with a varicocele do not have symptoms. When symptoms do occur, the most common ones include feeling a lump in the scrotum or feeling a broad heaviness or throbbing pain in the scrotum when standing for a long period of time. But most men do not know they have the health issue. A varicocele has been described as looking like a “bag of worms.”