A varicocele is an abnormal enlargement of the pampiniform venous plexus in the scrotum. In males, this plexus of veins drains blood from the testicles back to the heart. The vessels originate in the abdomen and course down through the inguinal canal as part of the spermatic cord on their way to the testis.

Many varicoceles are asymptomatic, but some cause a dull ache or a feeling of heaviness in the scrotum. Varicoceles are the most common correctable cause of male infertility, found in approximately 35–44% of men with primary infertility. They are also increasingly recognized as a cause of reduced testicular endocrine function, including lower testosterone levels (hypogonadism). Varicoceles occur in around 15% of all men. When palpable, the enlargement of veins above the testicle is most commonly left-sided (80–90% of cases). Right-sided and bilateral varicoceles also occur; an isolated right-sided varicocele is rare and may prompt investigation for an abdominal mass compressing the vena cava.

Testicular atrophy and growth arrest

Varicoceles are a known cause of testicular atrophy (shrinkage) in adults and growth arrest (failure to develop) in adolescents. The affected testicle is often significantly smaller than the unaffected side due to a loss of germ cell mass and seminiferous tubule diameter caused by heat stress and hypoxia. Treatment has been shown to result in "catch-up growth," where the affected testicle increases in volume and recovers size relative to the healthy testicle.

Pathophysiology

Fertility

The relationship between varicocele and infertility is complex. Mechanisms of damage include:

  • Hyperthermia: The pooling of warm blood disrupts the counter-current heat exchange, raising scrotal temperature and impairing spermatogenesis.
  • Oxidative Stress: Increased levels of Reactive oxygen species (ROS) damage sperm DNA and membranes.

Hormonal function

While historically linked to infertility, modern data indicates varicoceles also impair Leydig cell function. A 2024 systematic review and meta-analysis found that varicocele repair significantly increases serum total testosterone levels (by a mean difference of approximately 82–97 ng/dL) in men with clinical varicoceles and preoperative hypogonadism.

Diagnosis

The diagnosis of varicocele is primarily clinical, based on physical examination ("palpation"), and may be confirmed by imaging.

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File:trans varicocele.tif|Varicocele in ultrasound (left: testicle)

File:Varicocele.png|Diagram of a varicocele

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Clinical classification

The Dubin and Amelar (1970) grading system is the most commonly used clinical standard:

  1. Grade 1: Palpable only during the Valsalva maneuver.
  2. Grade 2: Palpable at rest, but not visible.
  3. Grade 3: Visible through the scrotal skin ("bag of worms") without manipulation.

Varicoceles that are not palpable but are detected solely by imaging are termed subclinical. Most guidelines do not recommend treatment for subclinical varicoceles unless there are specific indications. It categorizes varicoceles into five grades based on reflux location and vessel dilation:

  1. Grade I: Reflux occurs solely in the inguinal channel during the Valsalva maneuver; no scrotal deformation.
  2. Grade II: Reflux reaches the proximal (upper) pampiniform plexus during Valsalva; no scrotal deformation.
  3. Grade III: Reflux reaches the distal (lower) vessels during Valsalva; no scrotal deformation.
  4. Grade IV: Spontaneous reflux is present at rest and increases during Valsalva; scrotal deformation and possible testicular hypotrophy (shrinkage).
  5. Grade V: Spontaneous reflux at rest that does not increase with Valsalva; always accompanied by testicular hypotrophy.

Imaging criteria

Scrotal ultrasound is the standard modality for confirmation. According to ESUR guidelines (2020), the widely accepted criteria for diagnosis include:

  • Microsurgical subinguinal varicocelectomy: The surgeon makes a small incision near the groin and uses a high-powered operating microscope to identify and preserve the testicular artery and lymphatic vessels while ligating the veins. This approach yields the lowest recurrence and complication rates among surgical methods.
  • Testicular atrophy: Rare, resulting from accidental ligation of the testicular artery.

Percutaneous embolization

Embolization is a minimally invasive procedure performed by an interventional radiologist. A catheter is inserted through a vein in the neck or groin and guided into the gonadal vein under X-ray fluoroscopy.

  • Mechanism: The radiologist deploys platinum coils or injects a sclerosant foam to physically block (occlude) the vein.
  • Efficacy: Studies indicate that embolization has comparable efficacy to surgical ligation in improving semen parameters and pregnancy rates. It offers the advantages of a faster recovery time and a lower risk of complications such as hydrocele and incision-related pain compared to surgery.
  • Testosterone: Meta-analyses have shown that varicocele repair is associated with a statistically significant increase in serum testosterone levels in men with hypogonadism.

See also

References