May also be called: Scrotal Varices; Scrotal Varicose Veins A varicocele (VAR-uh-ko-seel) is an enlargement of the veins in the scrotum. More to Know In all males, there's a structure called the spermatic cord that contains arteries, veins, nerves, and tubes. It is connected to and circulates blood to and from the testicles. Veins in the spermatic cord carry blood from the testicles back to the heart, and valves in the veins regulate the blood flow and keep blood flowing in the right direction. If the valves fail, some of the blood can flow in reverse. This backed-up blood can collect in pools in the veins, which then causes the veins to stretch and swell, resulting in a varicocele. Varicoceles are fairly common, occurring in about 15% of males 15-25 years old, mostly during puberty. Varicoceles are usually found on the left side of the scrotum. Although it's less common, they can sometimes occur on both sides. Symptoms of a varicocele include discomfort in the testicle, a feeling of heaviness or dragging in the scrotum, and dilated veins in the scrotum that can feel like worms or spaghetti. Varicoceles are generally harmless, but some experts believe that occasionally they might damage the testicle or decrease sperm production. In those cases, a doctor will probably recommend surgery to treat the problem. Keep in Mind Most varicoceles don't require treatment and cause no symptoms. When treatment is recommended, it's usually successful at increasing sperm production and preventing further damage to the testicle. All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts. Back to Articles Related Articles Is It Normal for One Testicle to Be Bigger? Find out what the experts have to say. Read More PQ: I have a lump on one of my testicles. What should I do? Find out the answer to this personal question! Read More Ultrasound: Scrotum Doctors order a scrotal ultrasound when they're concerned about symptoms such as scrotal pain or swelling. Read More Varicocele A varicocele is an enlargement of the veins in the scrotum. Although there is no way to prevent a varicocele, it usually needs no special treatment. Read More What Should I Do About Lumps in My Testicles? Find out what the experts have to say. Read More Why Does the Doctor Have to Examine My Testicles? Find out what the experts have to say. Read More A to Z: Hydrocele A hydrocele is a collection of fluid around the testicle within the scrotum. Read More A to Z: Scrotal Pain, Acute A variety of things can cause pain in the scrotum (also called scrotal pain), the pouch-like structure at the base of a boy's penis. Read More Male Reproductive System What makes up a guy's reproductive system and how does it develop? Find the answers to these questions and more. Read More Male Reproductive System Understanding the male reproductive system and what it does can help you better understand your son's reproductive health. Read More Talking to Your Child About Puberty Talking to kids about puberty is an important job for parents, especially because kids often hear about sex and relationships from unreliable sources. Here are some tips. Read More Testicular Exams If you're a guy, you may be wondering why the doctor needs to do a testicular exam. Find out in this article. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.