When people hear the term “varicose veins,” they typically picture the swollen, twisted veins that can appear on the legs. However, a similar condition can occur in men within the scrotum, and it is surprisingly common. This condition is called a varicocele, an enlargement of the network of veins that drain blood from the testicle. While many varicoceles are harmless and cause no symptoms, they are considered the leading correctable cause of male infertility and can sometimes lead to testicular pain or a reduction in testicle size. Understanding this common condition is essential for any man concerned about scrotal health, pain, or his fertility potential.

A varicocele is a condition in which the veins within the scrotum (the pouch holding the testicles) become enlarged and swollen. These specific veins form a network called the pampiniform plexus, which is located within the spermatic cord, the structure that runs from the abdomen down to the testicles, containing the vas deferens (the sperm tube), arteries, and nerves.

The pampiniform plexus has two crucial functions. Its primary job is to carry oxygen depleted blood away from the testicle, returning it to the heart. Its second, equally important role is to act as a natural “heat exchanger.” The network of cooler venous blood surrounds the testicular artery, which carries warm arterial blood from the body. This setup cools the arterial blood before it reaches the testicle, helping to maintain the testicular temperature at a level slightly cooler than the core body temperature, which is optimal for healthy sperm production.

The veins throughout our body contain small, one-way valves that open to allow blood to flow toward the heart and then snap shut to prevent it from flowing backward. A varicocele develops when these valves within the pampiniform plexus fail to function correctly. This valve failure allows blood to flow backward and pool in the veins, causing them to stretch, twist, and enlarge.

Varicoceles are much more common on the left side (around 85% of cases) due to anatomical differences in how the left and right testicular veins connect to the larger circulatory system.

Analogy: Think of a varicocele like a traffic jam in the veins of the scrotum. Instead of blood flowing smoothly away from the testicle, it backs up, causing the veins to stretch and swell, like a balloon being overinflated.

Varicocele is caused by a failure of the one-way valves inside the scrotal veins. These valves are essential for helping blood flow upward against gravity, out of the scrotum and back to the heart. When these valves become weak or incompetent, they fail to close properly. This allows blood to flow backward (a process called reflux) and pool in the veins, increasing the pressure and causing them to dilate and become varicose.

The strong predilection for varicoceles to occur on the left side is due to a simple matter of plumbing. The right testicular vein drains into the large inferior vena cava at a gentle, downward angle, which is a low-pressure system. In contrast, the left testicular vein connects to the left renal (kidney) vein at a steep, 90-degree angle. This creates higher pressure in the left testicular vein, making it more difficult for the valves to function and for blood to drain efficiently, thus increasing the likelihood of blood pooling.

In very rare cases, a varicocele that appears suddenly in an older man can be a sign of a more serious problem, such as a kidney tumor that is compressing the renal vein and blocking blood outflow. However, the vast majority of varicoceles, especially those that develop during puberty, are not caused by any other medical condition.

Unlike many medical conditions, there are no well-established risk factors for developing a primary varicocele. It is not caused by any specific behavior, lifestyle choice, or activity. It is largely considered an anatomical or congenital issue. Most varicoceles develop during puberty. It is thought that during this period of rapid growth; the testicles require a significant increase in blood flow. This can overwhelm the venous drainage system, putting stress on the valves and leading to their failure in susceptible individuals. Therefore, the main “risk factor” for developing a varicocele is simply being male and going through puberty.

Many varicoceles are asymptomatic, meaning they cause no noticeable symptoms and are found during exams for unrelated issues, especially fertility assessments.

When symptoms do occur, they can include the following:

• A Palpable Mass: The most classic sign is a mass of twisted, enlarged veins in the scrotum that is often described as feeling like a “bag of worms.” This mass is usually located above the testicle and is easier to feel when standing up.
• A Dull, Aching Pain or Heaviness: Some men experience a dull, dragging, or aching pain in the scrotum. The pain often worsens during the day, with prolonged standing or physical exertion, and in hot weather. It typically feels better when lying down, as gravity no longer impedes blood flow.
• Testicular Atrophy (Shrinking): The affected testicle may be noticeably smaller than the other one. It is believed that the increased temperature and pressure from the pooled blood can impair testicular growth and health over time. This is a key reason for considering treatment in adolescents.
• Visible Veins: In large varicoceles (Grade 3), the swollen veins may be clearly visible through the skin of the scrotum.

The diagnosis of a varicocele is primarily made through careful physical examination by a urologist.

Physical Examination: The doctor will examine the scrotum while the patient is in a standing position, as this allows gravity to fill the veins, making them easier to feel. The doctor may ask the patient to perform the Valsalva maneuver (taking a deep breath, holding it, and bearing down as if having a bowel movement). This increases the pressure in the abdomen and can make a smaller varicocele more prominent and easier to detect.

Based on the physical exam, varicoceles are clinically graded on a 3-point scale:

• Grade 1: The smallest type. The varicocele is not visible and can only be felt when the patient is performing the Valsalva maneuver.
• Grade 2: The varicocele is not visible but is easily palpable (felt) without the Valsalva maneuver.
• Grade 3: The largest type. The varicocele is clearly visible through the scrotal skin.

Scrotal Ultrasound: A scrotal ultrasound with Doppler is often used to confirm the diagnosis and gather more detailed information. This non-invasive imaging test can:

• Visualize the network of enlarged veins and measure their diameter.
• Use the Doppler function to show the backward flow (reflux) of blood when the patient performs a Valsalva maneuver.
• Accurately measure the volume of each testicle to objectively assess for any size difference or atrophy.

Semen Analysis: If infertility is a concern, one or more semen analyses will be ordered.

Clinically, ultrasound is the most reliable way to confirm a varicocele, especially in borderline or non-palpable cases.

A crucial point is that most varicoceles do not require treatment. The decision to intervene is based on the presence of specific issues. The main reasons to treat a varicocele are:

1. Male Infertility: This is the most common reason for treatment. It is recommended for men in a couple with documented infertility who have a palpable varicocele and an abnormal semen analysis.
2. Testicular Atrophy: In an adolescent, evidence that the testicle on the side of the varicocele is not growing and the other side is a strong indication for repair to allow for potential “catch-up” growth.
3. Significant Pain: If a varicocele is causing persistent pain or discomfort that affects a person’s quality of life, treatment may be recommended.

The goal of any treatment is to block the abnormal, dilated veins of the pampiniform plexus. This forces the blood to re-route and drain through the smaller, healthy veins. This relieves the pooling of blood, which is thought to lower the temperature around the testicle and improve the overall testicular environment, potentially leading to improved sperm production and testosterone function.

There are two main approaches to treatment:

1. Surgical Repair (Varicocelectomy): This is the most common treatment method. The surgeon makes a small incision and, using various techniques, identifies and ties off (ligates) all the abnormal veins.

• Microsurgical Varicocelectomy: It is the gold standard for surgical repair. It is performed through a small incision in the groin. The surgeon uses a powerful operating microscope to magnify the spermatic cord structures. This allows for precise identification and ligation of all the small, abnormal veins while carefully preserving the critical structures, the testicular artery, the vas deferens, and the lymphatic vessels. This technique has the highest success rates and the lowest rates of complications, such as hydrocele formation (fluid around the testicle) or damage to the testicular artery.

2. Percutaneous Embolization: This is a less invasive, non-surgical procedure performed by an interventional radiologist.

• The radiologist inserts a tiny catheter into a large vein, usually in the groin or neck, and guides it using X-ray imaging to the testicular vein.
• Once in place, tiny metal coils or a special sclerosing agent (a solution that causes scarring) are deployed into the vein. These materials create a blockage that stops the backward flow of blood, effectively closing off the varicocele from the inside. Embolization offers a faster recovery time but may have a slightly higher recurrence rate than microsurgery in some cases.

A varicocele is a common anatomical variation that, for most men, will never cause a problem. However, for a significant number, it represents a treatable cause of pain, testicular growth impairment, or infertility. The classic “bag of worms” description, the potential for a dull, aching sensation, and its strong link to abnormal semen parameters are its key features. While the diagnosis can be concerning, it is important to remember that not all varicoceles require intervention. For those that do, modern microsurgical and radiological techniques offer highly effective solutions that can relieve symptoms, improve testicular health, and offer a real chance at improving fertility.

• American Urological Association. (2014). Report on varicocele and infertility. Retrieved from https://www.auanet.org/guidelines/guidelines/varicocele-and-infertility
• Urology Care Foundation. (2023). Varicoceles. Retrieved from https://www.urologyhealth.org/urology-a-z/v/varicoceles
• Cleveland Clinic. (2023). Varicocele. https://my.clevelandclinic.org
• Mayo Clinic. (2023). Varicocele. https://www.mayoclinic.org