ConditionMen's health
Epididymal Cyst (Spermatocele)
An epididymal cyst is a smooth, fluid-filled lump in the epididymis, the coiled tube that sits on top of and behind each testicle. When the fluid contains sperm it is called a spermatocele. These cysts are very common, especially after age 40, and are almost always benign. They are usually painless and feel separate from the testicle. Any new scrotal lump should be checked by a doctor, but most epididymal cysts need no treatment unless they become large or uncomfortable.
Also called: Spermatocele, epididymal cyst of the testicle, seminal cyst, testicular cyst (common term)
At a glance
- What it is
- A benign fluid-filled sac in the epididymis, above and behind the testicle.
- How common
- Very common; found on ultrasound in many adult men, most often after 40.
- How it feels
- Smooth, round, soft or firm, usually painless, separate from the testicle.
- Cancer risk
- Not cancerous and does not turn into cancer.
- Diagnosis
- Examination and scrotal ultrasound.
- Treatment
- Usually none; surgery if large, painful or bothersome.
When to get help
Call 911 or go to the ER
- Sudden, severe testicle pain, often with nausea or vomiting, or a testicle sitting higher than usual (possible testicular torsion): call 911 or go to the ER immediately
See a doctor within a day or two
- A painful, red, hot, swollen scrotum with fever (possible epididymitis or infection)
- A firm lump on the testicle itself, or a testicle that feels heavier or harder
- A scrotal swelling that gets bigger when you cough or strain and is painful (possible hernia)
Book a routine appointment
- Any new lump in the scrotum, to confirm what it is
- A known cyst that is growing, aching or uncomfortable
- A lump that makes walking, sitting or exercise uncomfortable
Where epididymal cysts form
Each testicle has an epididymis attached to its upper back surface. Sperm made in the testicle mature and are stored in the epididymis before passing into the vas deferens. A cyst forms when part of this tubing becomes blocked or dilated and fills with fluid. Cysts can be single or multiple, on one or both sides, and range from a few millimeters to several centimeters.
There is a technical difference between an epididymal cyst (clear fluid) and a spermatocele (fluid containing sperm), but they look and behave the same and are treated the same way. See spermatocele.
Causes
The cause is usually unknown. Cysts are thought to arise from blockage of small ducts in the epididymis. Possible links include:
- aging
- previous epididymitis or injury
- vasectomy (for spermatoceles)
- in some men, exposure in the womb to the hormone diethylstilbestrol (DES)
- von Hippel-Lindau disease, which can cause cysts and benign tumors of the epididymis
Symptoms
- a smooth, round lump above or behind the testicle, often the size of a pea to a grape
- usually painless
- a dull ache, heaviness or dragging feeling if large
- the testicle itself feels normal
- may be noticed during self-examination or by a partner
Epididymal cyst vs other scrotal lumps
| Condition | Clues |
|---|---|
| Epididymal cyst | Smooth, separate lump above or behind the testicle; testicle normal |
| Testicular cancer | Firm, painless lump within the testicle itself; usually men 15 to 40 |
| Hydrocele | Fluid around the whole testicle; smooth, soft swelling you cannot feel above |
| Varicocele | "Bag of worms" feel above the testicle, usually left side, worse standing |
| Inguinal hernia | Swelling from the groin into the scrotum, bigger with coughing, may go back in |
| Epididymitis | Painful, tender, swollen epididymis, often with fever or urinary symptoms |
| Testicular torsion | Sudden severe pain, swollen high-riding testicle; an emergency |
Shining a flashlight through the scrotum (transillumination) makes a cyst glow, while a solid lump does not. This is a quick clinic test, but ultrasound is more reliable.
Diagnosis
A doctor examines the scrotum while you are standing and lying down, feeling the testicle, epididymis and spermatic cord separately. A scrotal ultrasound confirms a fluid-filled cyst in the epididymis and checks the testicle for any other abnormality. It is quick, painless and uses no radiation.
Treatment
Watchful waiting
Most epididymal cysts need no treatment. They often stay the same size for years and sometimes shrink. Recheck if a cyst grows, becomes painful, or your other testicle changes.
Pain relief
For an occasional ache, supportive underwear and over-the-counter pain relievers at the label dose may help.
Surgery (spermatocelectomy or cyst excision)
Considered when a cyst is large, painful, or bothersome. The cyst is removed through a small cut in the scrotum, usually as day surgery. Considerations:
- swelling and bruising for 1 to 2 weeks
- small risks of infection, bleeding (hematoma) and recurrence
- possible scarring or blockage of the epididymis that could affect fertility on that side, so surgery is often delayed in men who want more children
Draining with a needle (aspiration) or injecting a sclerosing agent is sometimes used, but cysts often refill and these methods carry fertility and infection risks.
Testicular self-examination
Checking your testicles monthly helps you know what is normal:
- Examine after a warm shower, when the scrotum is relaxed.
- Roll each testicle gently between your thumb and fingers.
- Feel the epididymis, a soft, comma-shaped structure at the top and back; this is normal.
- Report any new lump, hardness, change in size or heaviness.
Frequently asked questions
Is an epididymal cyst serious?
No. Epididymal cysts are benign, common and do not turn into cancer. They usually cause no symptoms and need no treatment. However, every new scrotal lump should be checked by a doctor to confirm the diagnosis and rule out a lump in the testicle itself.
How do I know if a lump is a cyst or testicular cancer?
A cyst usually feels like a smooth, separate lump above or behind the testicle. Cancer usually feels like a firm or hard lump within the testicle itself. You cannot be sure by touch alone, so an ultrasound is used to tell them apart.
Do epididymal cysts go away on their own?
Some shrink or disappear, but many stay the same size for years. Since they are harmless, they can simply be monitored. Surgery is only needed if a cyst becomes large, painful or bothersome.
Can an epididymal cyst affect fertility?
The cyst itself rarely affects fertility. Surgery to remove it can sometimes block the epididymis on that side, which is why doctors may delay surgery in men who plan to have children. Fertility usually remains normal if the other side is healthy.
Sources
This guide was written from current patient and clinical guidance, including:
- American Urological Association: Urology Care Foundation, spermatocele
- MedlinePlus: Spermatocele
- NHS: Epididymal cysts
- American Academy of Family Physicians: Evaluation of scrotal masses
- European Association of Urology: Guidelines on paediatric and adult scrotal conditions