Epididymal Cyst
A benign fluid-filled lump behind the testicle
Quick Facts
- Type: Benign scrotal lump
- Location: Epididymis, behind the testicle
- Usual symptoms: Painless, smooth lump
- Seek care: Sudden severe testicle pain or rapid swelling
Overview
An epididymal cyst is a smooth, fluid-filled lump that develops in the epididymis, the small coiled tube that lies behind and above each testicle and carries sperm. These cysts are very common, almost always harmless (benign), and not a form of cancer. When the cyst fluid contains sperm, it is often called a spermatocele.
Most epididymal cysts cause no symptoms and are found by chance during a self-examination or a routine check-up. They can stay the same size for years, grow slowly, or occasionally shrink. While the lump itself is not dangerous, any new lump in the scrotum should be checked by a doctor to be sure of the cause. Finding a lump can be frightening, but it helps to know that epididymal cysts are among the most common scrotal lumps and are almost always harmless. The main reason to have one examined is simply to confirm that it is a cyst and not one of the rarer causes of a scrotal lump that need different treatment.
Symptoms
Epididymal cysts are usually painless and may be noticed only when feeling the scrotum.
- A smooth, round, movable lump behind or above the testicle
- A feeling of fullness or heaviness in the scrotum, especially if the cyst is large
- Usually no pain, though a large cyst can cause mild aching
The testicle itself feels normal and separate from the cyst. Sudden, severe pain, redness, or rapid swelling of the scrotum is not typical of a cyst and needs urgent care, because it can signal a twisted testicle (testicular torsion) or infection.
Causes
The exact reason epididymal cysts form is not always clear. They are thought to result from a blockage or buildup of fluid in the tubes of the epididymis.
- Fluid buildup: A small tube that drains the epididymis can become blocked, causing fluid and sometimes sperm to collect and form a cyst.
- Natural variation: Many cysts develop without any clear trigger and are simply part of normal variation.
Epididymal cysts are not caused by injury, sexual activity, or anything a person did wrong, and they are not a sexually transmitted infection.
Risk Factors
- Adult age (they become more common with age and are uncommon before puberty)
- A previous epididymal cyst
- Generally no other clear risk factors
Diagnosis
A doctor can often identify an epididymal cyst from an examination, but imaging confirms the diagnosis and rules out other causes of a scrotal lump.
- Physical exam: The doctor feels the lump and may shine a light through it (transillumination); fluid-filled cysts usually let light pass through.
- Scrotal ultrasound: The key test, which clearly shows a fluid-filled cyst and distinguishes it from a solid lump that would need further evaluation.
Treatment
Most epididymal cysts need no treatment because they are harmless and cause no symptoms.
- Watchful waiting: Reassurance and occasional self-checks are usually all that is needed.
- Pain relief: Simple measures such as supportive underwear and over-the-counter pain relievers help if a large cyst causes mild discomfort.
- Surgery: Removal of the cyst is considered only if it becomes large, painful, or bothersome. This is a minor operation, though it is usually avoided in younger men who may wish to have children, as it can affect the epididymis.
Draining a cyst with a needle is generally not advised because cysts tend to refill. For most people, the best approach is simply to be reassured, to keep up with regular self-examination, and to return for review only if the cyst grows, becomes painful, or changes in a way that concerns them.
Prevention
There is no known way to prevent epididymal cysts, since their cause is not fully understood. However, regular testicular self-examination is worthwhile:
- Check your testicles monthly so you become familiar with what is normal for you
- Report any new lump, change in size, or new pain to a doctor
- Knowing your usual anatomy makes it easier to spot changes that need attention
When to See a Doctor
See a doctor for any new lump in the scrotum so the cause can be confirmed. Seek urgent or emergency care if you have:
- Sudden, severe pain in a testicle
- Rapid swelling, redness, or warmth of the scrotum
- Fever along with scrotal pain or swelling
- A firm, hard, or rapidly growing lump on the testicle itself
Sudden severe testicle pain can be a sign of a twisted testicle, which is an emergency that needs treatment within hours.
Frequently Asked Questions
Is an epididymal cyst cancer?
No. An epididymal cyst is a benign fluid-filled lump, not cancer. It feels separate from the testicle and usually lets light pass through it. Still, any new scrotal lump should be checked by a doctor and confirmed with an ultrasound.
Does an epididymal cyst need to be removed?
Usually not. Most cause no symptoms and can simply be left alone and monitored. Surgery is considered only if the cyst becomes large, painful, or bothersome, and it is often avoided in men who may want to have children.
Can an epididymal cyst affect fertility?
A small cyst on its own does not usually affect fertility. Surgery to remove a cyst can occasionally affect the epididymis, which is why removal is approached cautiously in younger men. Discuss any fertility concerns with your doctor.
How can I tell an epididymal cyst from something serious?
A cyst is typically a smooth, painless, movable lump behind the testicle, while the testicle itself feels normal. Sudden severe pain, a hard lump on the testicle, or rapid swelling are not typical of a cyst and need prompt medical evaluation.
Will an epididymal cyst go away on its own?
Some cysts shrink, some stay the same, and some grow slowly over time. They do not usually disappear completely, but because they are harmless, no treatment is needed unless they cause symptoms.
References
- MedlinePlus, U.S. National Library of Medicine. Spermatocele.
- Mayo Clinic. Spermatocele (epididymal cyst).
- Urology Care Foundation. Scrotal masses.
- National Library of Medicine, StatPearls. Spermatocele.