Epididymal Cyst
Evaluation and treatment of a fluid-filled cyst arising near the epididymis when symptomatic or concerning
What is epididymal cyst?
An epididymal cyst is a fluid-filled sac that grows from the epididymis, the coiled tube that sits along the back and top of the testis and carries sperm away from it. The cyst is part of that tube system and sits separate from the testis itself, which is the single most useful thing to know about it.
They form when one of the fine tubes carrying sperm becomes obstructed and the fluid behind the blockage collects. Where the trapped fluid contains sperm the swelling is called a spermatocele; the two behave the same way. Nobody can usually say why a particular tube blocked, and there is nothing you did to cause it.
They are common and they become more common with age. A great many men over forty have one without ever knowing, and they are found by chance during an examination or a scan done for something else. An epididymal cyst is a benign swelling. It does not turn into anything else, and it does not affect the hormones the testis produces.
What you might notice
- A lump felt in the testicle
- A swelling of the scrotum that has grown slowly
- A dragging ache in the scrotum
How it is diagnosed
The examination is the diagnosis, and an experienced doctor can usually be confident within a minute. They feel the scrotum with the flat of the fingers, establish where the swelling sits in relation to the testis, and try to define its upper edge.
Three things are being checked. Whether the swelling is separate from the testis and above it, which an epididymal cyst is and a swelling of the testis itself is not. Whether it is smooth and fluid-filled, tested by holding a light against the scrotum in a dark room and seeing whether the light passes through. And whether the testis underneath it feels entirely normal.
A scrotal ultrasound is arranged where any of those three is uncertain, where there is more than one swelling, or where the testis cannot be felt clearly around the cyst. Your doctor will examine both sides, because these are often present on both and comparing them is informative. Any firm lump that appears to arise from the testis itself is investigated on its own terms and promptly.
Recovery
Most epididymal cysts need no treatment at all. Once the examination has established what it is, the usual advice is to leave it alone, note what size it is now, and come back if that changes. There is no medicine that shrinks one.
Where a cyst is large or heavy enough to be a nuisance and an operation is chosen, it is a Day Care procedure. Expect a supportive garment for a week, a dull ache and bruising for one to two weeks, desk work within two to three days, no cycling or heavy lifting for two weeks, and no sexual activity for about three weeks. The stitches are dissolvable.
Swelling of the scrotum after any operation on it settles more slowly than people expect, and six weeks to look completely normal is usual. Your surgeon will see you at about two to four weeks to check the wound.
If it is left untreated
Leaving an epididymal cyst alone is a reasonable and common choice. Most stay the same size for years, and a proportion get slowly larger without ever becoming a problem.
What can happen if it is left is mechanical. A cyst that keeps growing becomes heavy and drags, and a large one is uncomfortable to sit with and to exercise around. Occasionally one bleeds into itself or becomes inflamed, which is briefly painful and settles with rest and simple painkillers. None of this is dangerous, and none of it is made worse by having waited.
The reason to be examined once and not simply assume is that a swelling you have decided is a cyst has not been diagnosed. A firm lump arising from the testis itself is a different problem entirely, it is most common in men between twenty and forty, and it is highly treatable when it is found early.
Sudden severe pain in one testis, with or without a known cyst, needs a hospital the same hour.
Questions about epididymal cyst
Could this be cancer?
An epididymal cyst is benign and does not become anything else. The distinction that matters is where the swelling arises. A cyst of the epididymis is separate from the testis and sits above and behind it, is smooth and fluid-filled, and light passes through it. A cancer arises within the testis itself and feels like a firm lump that is part of the testis and cannot be separated from it. That is a distinction a doctor makes on examination in a minute, and an ultrasound settles anything unclear the same day. Any firm lump in the testis should be examined promptly.
Will it affect my fertility?
The cyst itself does not. It is a blocked side-tube that has filled with fluid, and the testis behind it works normally and continues to produce sperm and testosterone. Men with cysts on both sides father children in the ordinary way. What can affect fertility is surgery on the epididymis, since operating close to those fine tubes can scar and block them, and that is one reason surgeons are cautious about removing a cyst in a younger man who has not completed his family. Raise this before agreeing to an operation so the risk is weighed properly.
Can it be drained instead of operated on?
Draining the fluid with a needle empties the cyst and is quick, and the cyst almost always refills over weeks to months because the lining producing the fluid is still there. It is sometimes used where somebody needs temporary relief or is not fit for surgery. Injecting an agent afterwards to stick the lining together makes a refill less likely, at the cost of inflammation and a period of discomfort. Your urologist will talk through whether either suits you, and will usually suggest simply leaving a cyst alone unless it is large enough to be a genuine nuisance.
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Leave a number and a care coordinator calls you back with what the treatment involves and which hospital it would be at. They book a consult only if you want one