- A spermatocele is a benign, fluid-filled cyst that forms on the epididymis, the tube behind the testicle, and is common in adult men.
- Most spermatoceles are painless and cause no symptoms; larger ones can bring a dull ache, heaviness, or scrotal swelling.
- Spermatoceles are not cancerous and don't raise the risk of testicular cancer, but any new scrotal lump should be checked by a clinician.
- Diagnosis usually involves a physical exam, transillumination (shining a light), and often an ultrasound to confirm it is a simple cyst.
- Small, painless spermatoceles typically need no treatment; surgery (spermatocelectomy) is considered mainly for persistent pain.
- Sudden, severe testicular pain and swelling is a medical emergency that needs urgent care, as it can signal a different, serious problem.
PASTE BELOW THIS LINE INTO THE WORDPRESS EDITOR
— (everything below is the HTML body) —
Finding a lump near a testicle is understandably alarming. Often, though, the cause turns out to be a spermatocele — a benign, fluid-filled cyst on the tube behind the testicle. Spermatoceles are common, usually harmless, and frequently need no treatment at all. That said, any new scrotal lump deserves a clinician’s eye, because reassurance should come from an exam, not from an article. This guide explains what a spermatocele is, what it feels like, how it is diagnosed, when treatment is considered, and the warning signs that mean you should not wait. It is general education, not medical advice.
What a spermatocele is
A spermatocele — also called an epididymal cyst — is a fluid-filled cyst that develops from the epididymis, the coiled tube that sits behind each testicle and stores and carries sperm. Cleveland Clinic describes the cyst as containing clear or cloudy fluid that may include sperm. It typically sits above or behind the testicle rather than within it, and it feels like a smooth, firm lump.
These cysts are common: Cleveland Clinic notes they affect nearly one in three adult males. The exact cause is not fully understood. The leading idea is that fluid and sperm build up when part of the epididymis becomes blocked or inflamed, but many spermatoceles appear without any sign of injury, infection, or other obvious trigger. Crucially, a spermatocele is benign — Cleveland Clinic is explicit that it does not raise the risk of testicular cancer.
Symptoms: often none at all
Many spermatoceles cause no symptoms and are discovered by chance, during a self-exam or a routine check-up. They also tend to stay stable in size. When a spermatocele is larger, Mayo Clinic and Cleveland Clinic note it can cause:
- A dull ache or discomfort in the testicle or scrotum
- A feeling of heaviness or fullness in the scrotum
- Visible or palpable swelling above or behind the testicle
Size varies widely — from too small to notice, to a pea-sized lump, to occasionally a growth large enough that people describe it as feeling like a “third testicle.” Importantly, spermatoceles themselves do not cause infertility, according to Cleveland Clinic.
When to see a doctor
Because it is not possible to be certain what a lump is by feel alone, the safe rule is simple: have any new scrotal lump, swelling, heaviness, or pain evaluated by a clinician. You will often start with a primary care provider, who may refer you to a urologist (a specialist in the urinary tract and male reproductive organs). Getting checked is not about expecting bad news — most lumps like this are benign — but a proper exam is how a spermatocele is distinguished from other conditions, including a hydrocele (a different kind of fluid collection) and, rarely, more serious causes.
Red flags that need urgent care
Some symptoms should not wait for a routine appointment. Seek emergency care for sudden, severe testicular pain and swelling, which Cleveland Clinic flags as needing urgent evaluation. Sudden severe scrotal pain can signal testicular torsion — a twisting that cuts off blood supply and is a time-critical emergency — rather than a simple cyst. Likewise, a lump that grows quickly, a hard mass that feels part of the testicle itself, or pain with fever should be assessed promptly. When in doubt about severe or sudden symptoms, treat it as urgent.
| Usually routine (get checked, not urgent) | Urgent / emergency |
|---|---|
| A new, painless, smooth lump above the testicle | Sudden, severe testicular pain |
| Mild, dull scrotal ache or heaviness | Rapid swelling of the scrotum |
| A lump that has been stable over time | Pain with fever, nausea, or vomiting |
How a spermatocele is diagnosed
Diagnosis usually starts with a physical exam of the scrotum. Two simple, common steps help confirm it:
- Transillumination. A clinician shines a light against the scrotum; a fluid-filled spermatocele tends to look partly see-through (translucent), which helps distinguish it from a solid mass.
- Ultrasound. This painless imaging test looks at the cyst in detail and helps confirm that it is a simple, benign fluid collection rather than something solid, as Mayo Clinic describes.
If there is pain, a clinician may also order lab tests to rule out infection. The goal of the workup is both to confirm the spermatocele and to make sure nothing else is going on.
Treatment: often watchful waiting
Here is the reassuring part: most spermatoceles do not need treatment. If a cyst is small and painless, the usual approach is simply to leave it alone and keep an eye on it, according to Mayo Clinic and the Urology Care Foundation. Treatment enters the picture mainly when a spermatocele causes ongoing pain, discomfort, or bother from its size.
When treatment is warranted, the main option is a surgical procedure called a spermatocelectomy. It is typically done on an outpatient basis under local or general anesthesia, with a urologist separating the cyst from the epididymis through a small scrotal incision. Less commonly, fluid can be drawn out with a needle (aspiration), sometimes followed by injecting an irritating solution to discourage it from refilling (sclerotherapy); these are used rarely. Every option carries trade-offs to discuss with a urologist — notably, surgery near the epididymis carries some risk of affecting fertility on that side, which is one reason painless cysts are often just monitored. The right choice depends on your symptoms, your priorities, and a specialist’s assessment.
Frequently asked questions
Is a spermatocele cancer? No. A spermatocele is benign and does not increase the risk of testicular cancer — but any new lump should still be examined to confirm what it is.
Does it hurt? Usually not. Most are painless; larger ones can cause a dull ache or a sense of heaviness.
Will it affect my fertility? The cyst itself does not cause infertility. Surgery to remove one carries some risk to fertility on that side, which is worth discussing before any procedure.
Do I need surgery? Often not. Small, painless spermatoceles are typically just monitored; surgery is mainly considered for persistent pain or bother.
How is it told apart from a hydrocele? Exam findings, transillumination, and ultrasound help distinguish a spermatocele from a hydrocele and other causes.
When is it an emergency? Sudden, severe testicular pain and swelling needs urgent care, as it can point to torsion rather than a simple cyst.
This article is general education and is not medical advice. Talk to a qualified clinician about your situation.
For more on conditions, symptoms, and when to seek care, see our medical conditions guide.
Sources
- Cleveland Clinic — Spermatocele: Causes, Symptoms, Diagnosis & Treatment (definition, prevalence, symptoms, benign nature, diagnosis, treatment, emergency signs)
- Mayo Clinic — Spermatocele: Symptoms & causes; Diagnosis & treatment (symptoms, when to see a doctor, transillumination and ultrasound, watchful waiting, spermatocelectomy, aspiration/sclerotherapy)
- Urology Care Foundation — Spermatoceles (overview, diagnosis, and treatment considerations)