There are a few key factors that can lead to enlarged testicles or “big balls” in men. The most common causes include varicoceles, hydroceles, spermatoceles, and testicular cancer. Varicoceles are enlarged veins in the scrotum and are present in around 15% of men. Hydroceles occur when fluid builds up around the testicle and causes swelling. Spermatoceles are fluid-filled cysts that arise from the epididymis and can grow quite large. Testicular cancer, while less common, can also present with testicular enlargement. Other less frequent causes include infections like epididymitis, trauma, testosterone imbalance, and medications. In many cases, there are no symptoms associated with enlarged testicles. However, some men may experience pain, swelling, hardness of the testicle, or a feeling of heaviness in the scrotum. If significant testicular enlargement occurs, especially on one side, it is important to see a doctor for evaluation. An ultrasound is usually recommended to assess testicular anatomy and determine the underlying cause. Treatment depends on the specific diagnosis but may include surgery, medication, or close observation. Catching and addressing testicular abnormalities early leads to better outcomes.
What is a varicocele?
A varicocele is an enlargement of the veins that drain blood from the testicles. It is the most common reversible cause of male infertility. Varicoceles often form during puberty, when there is increased blood flow to the testicles. However, they can occur in men of any age. Up to 15% of men have a varicocele. They are more common on the left side, since the left testicular vein drains at a right angle into the left renal vein, whereas the right testicular vein enters the inferior vena cava at a more direct angle. The backup of blood in the veins puts pressure on the testicle and causes it to enlarge. Varicoceles are graded based on severity:
- Grade 1 – Palpable only with Valsalva maneuver (attempting to exhale with nostrils and mouth closed)
- Grade 2 – Palpable at rest but not visible
- Grade 3 – Visibly enlarged veins when standing
Higher grade varicoceles tend to be more symptomatic. The enlarged venous structure may feel like a “bag of worms” above the testicle. Symptoms associated with varicoceles include:
- Aching pain/discomfort in the scrotum, often worse with exercise
- Feeling of heaviness in the scrotum
- Visible enlargement of the veins in the scrotum
- Shrinkage or loss of size/shape of the testicle
- Infertility
Varicoceles can cause increased scrotal temperature, blood pooling, venous pressure, testicular hypoxia, and oxidative stress, which impair sperm production and quality. Surgical repair is often recommended for symptomatic varicoceles and can improve semen parameters and fertility. Treatment options include:
- Varicocelectomy – Minimally invasive surgery to ligate the dilated veins
- Embolization – Blocking the veins through a radiology procedure
- Varix ligation – Open surgical approach to tie off the veins
After surgical repair, the testicle often decreases in size and there is relief of discomfort. With successful treatment of the varicocele, sperm function may improve in up to two-thirds of men. Pregnancy rates also increase for couples trying to conceive.
What is a hydrocele?
A hydrocele is a fluid collection that causes swelling around the testicle. Hydroceles are common in newborns but can also affect boys and adult men. In infants, hydroceles often resolve on their own by age 1. In older males, hydroceles may develop from inflammation/infection, trauma, surgery, or deficiency of the lymphatic drainage system. There are two types:
1. Simple hydrocele – Collection of fluid between the layers of the tunica vaginalis, which is a sac surrounding the testicle. This causes nonspecific enlargement of the scrotum.
2. Communicating hydrocele – Fluid accumulation from the abdomen through a patent processus vaginalis, which is an opening between the tunica vaginalis and the abdominal cavity that sometimes fails to close after birth. This causes a hydrocele that varies in size.
Symptoms of a hydrocele include:
- Swelling in one side of the scrotum, sometimes painless
- Heaviness/dragging sensation in the scrotum
- Scrotum may be tense yet fluctuate in size
- Difference in size between testicles
- Discomfort with prolonged standing
Hydroceles are diagnosed through a scrotal ultrasound, which will show fluid surrounding the testicle. Most hydroceles do not pose any threat to fertility or testicular function. However, treatment may be pursued for bothersome symptoms or very large hydroceles. Options include:
- Aspiration – Draining the fluid with a needle, often recurs
- Sclerotherapy – Injecting a sclerosing solution to prevent reaccumulation
- Surgery – Making an incision to drain and excise the tunica vaginalis
After surgical repair, the testicle will return to its normal size. Aspiration or sclerotherapy may need to be repeated for recurring fluid buildup.
What is a spermatocele?
A spermatocele is a usually painless, noncancerous cyst that grows in the epididymis, which stores and transports sperm. Spermatoceles are fluid-filled sacs that arise from the epididymis. They occur most often in men ages 30-40 years old. Spermatoceles are believed to form due to ductal obstruction, infections, surgery, or trauma in the epididymis. This causes a cyst to form that fills with sperm and fluid and can grow quite large. On exam, a spermatocele will feel like a separate mass adjacent to the testicle, unlike a hydrocele which surrounds the testicle. Symptoms associated with spermatoceles include:
- Mass or lump on the epididymis, above and behind the testicle
- Heaviness or fullness in the scrotum
- Swelling/enlargement of the scrotum
- Size fluctuation of the mass
- Painless in most cases
Diagnosis of a spermatocele is made by scrotal ultrasound, which will show a fluid-filled cystic mass in the epididymis separate from the testicle. While spermatoceles often do not cause problems, some men may experience pain or discomfort from the enlarging cyst. Treatment options for symptomatic cases include:
- Aspiration – Drainage of the cyst fluid with a needle
- Sclerotherapy – Injection of a sclerosing solution into the cyst to shrink it
- Surgery – Excision of all or part of the cyst
If a spermatocele grows very large, it can potentially affect sperm quality by obstructing ducts. However, fertility is usually maintained. After drainage procedures, the spermatocele may eventually recur and require repeat aspiration or surgery. Otherwise, observation is often the standard approach.
Can testicular cancer cause testicle enlargement?
Yes, one of the first signs of testicular cancer can be testicular enlargement or the development of a painless lump/mass in a testicle. Testicular cancer is most common between ages 20-40, but can occur at any age. Risk factors include undescended testicle(s), family history, previous germ cell tumor, and Caucasian race. Testicular self-exams allow men to check regularly for any new masses or testicular changes.
Some key warning signs of testicular cancer include:
- Lump, mass, or swelling in a testicle, often painless
- Feeling of heaviness or achiness in the scrotum
- Buildup of fluid in the scrotum (hydrocele)
- Enlargement or swelling of a testicle
- Pain, discomfort, or numbness in the testicle, abdomen, groin, lower back
Of testicular cancers, about 90% are germ cell tumors which start from sperm-producing cells in the testicles. The other 5% are stromal tumors from connective tissue cells in the testicles. Testicular cancer has high cure rates if caught early. A testicular exam and scrotal ultrasound are recommended for confirmation. Treatment options include:
- Surgery – Radical inguinal orchiectomy to remove the affected testicle and spermatic cord.
- Chemotherapy – Cisplatin combination regimens, sometimes before or after surgery.
- Radiation therapy – In select cases of early stage cancer.
- Retroperitoneal lymph node dissection – For certain cases of spread to the lymph nodes.
Despite loss of a testicle, sperm production and fertility are usually retained from the remaining testicle. However, sperm banking may be considered prior to treatment. With prompt diagnosis and management of testicular cancer, the majority of men go on to live long, healthy lives.
What other conditions can cause enlarged testicles?
Some less common causes of testicular enlargement include:
Epididymitis – Inflammation of the epididymis causing swelling and pain. Often due to infection.
Orchitis – Inflammation of the testicle itself, may cause fever and tenderness. Usually from infection.
Testosterone imbalance – Excess testosterone, from steroids or testicular tumors, can increase testicle size. Low testosterone can impair development.
Hydrocele of the cord – Rare fluid collection in the spermatic cord above the testicle.
Inguinal hernia – Portion of intestine enters the inguinal canal near the testicle, causing swelling.
Hematocele – Bleeding into the space around the testicle, called the tunica vaginalis.
Trauma – Direct injury to the testicle can cause blood clots or swelling. Wearing protective athletic gear reduces risk.
Testicular torsion – Twisting of the spermatic cord cuts off blood flow to the testicle. Requires emergency surgery.
Pubertal changes – Testicles enlarge significantly during puberty due to hormonal shifts. Usually symmetric growth.
Medications – Certain medicines like androgens, anabolic steroids can increase testicle size when abused.
If testicular swelling arises, prompt medical evaluation is recommended for accurate diagnosis. Underlying testicular cancer needs to be excluded. Treatment will depend on the specific cause identified. Most cases of testicular enlargement are benign and manageable. However, monitoring for any worsening asymmetry or symptoms is advised.
Conclusion
There are a variety of different conditions that can lead to enlargement or swelling of the testicles. The most frequent causes are varicoceles, hydroceles, spermatoceles, and testicular cancer. Other less common causes include infections, medications, trauma, torsion, and hormonal disorders. In many cases, there are no pain or symptoms associated with the testicular enlargement. However, some patients experience heaviness, swelling, lumps, or asymmetry of the testicle size. If significant or persistent testicular enlargement occurs, especially in only one testicle, prompt medical evaluation is recommended. This will help identify the underlying cause based on exam, ultrasound, and any needed lab tests or scans. Treatment options will then depend on the specific diagnosis. Addressing abnormal testicular enlargement is important to preserve fertility and avoid complications. With proper management, outcomes for testicular swelling are often excellent.
