A varicocele is when veins become enlarged inside your scrotum (the pouch of skin that holds your testicles). These veins are called the pampiniform plexus. Ten to 15 of every 100 males have a varicocele. It is like getting a varicose vein in your leg.
The male reproductive system makes, stores, and moves sperm. The scrotum is the sac of skin that holds the testicles (testes). Sperm and the hormone testosterone are made in the testicles. Sperm mature while moving through a coiled tube (the epididymis) behind each testicle.
Sperm travel to the prostate from each epididymis using a tube called the vas deferens. When you ejaculate, seminal fluid mixes with sperm in the prostate to form semen. The semen travels through the urethra and comes out the end of your penis.
The spermatic cord holds the vas deferens and the testicular artery, which brings blood to the testicle. It also houses the pampiniform plexus, a group of connected veins that drains the blood from the testicles. The pampiniform plexus cools blood in the testicular artery before it enters the testicles. This helps keep it at the temperature needed to make sperm.
Varicoceles are when the pampiniform plexus veins in the scrotum become enlarged. These veins are like varicose veins in the leg. Varicoceles form during puberty, and can grow larger and easier to notice over time. Varicoceles are more common on the left side of the scrotum. This is because the male anatomy isn’t the same on both sides. Varicoceles can exist on both sides at the same time, but this is rare. About 10 to 15 boys out of 100 have a varicocele.
Most of the time, varicoceles cause no problems and are harmless. Less often varicoceles can cause pain, problems fathering a child, or 1 testicle to grow slower or shrink.