Epididymal cyst: what is it, symptoms, causes, treatment

Epididymal cysts are a type of growth in the scrotum. Finding a lump down there is alarming, and your mind may either jump to a worst-case scenario like cancer or experience feelings of self-consciousness because your testicles look or feel different.

While you should always contact your physician if you notice an abnormal growth, epididymal cysts are harmless and may not require treatment. They are not contagious, do not impact fertility, and often aren’t painful (O’Kelly, 2019; Weatherly, 2018). Getting a confirmed diagnosis from a medical professional can alleviate worry and clarify what that lump is. 

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An epididymal cyst is a fluid-filled lump in the epididymis—a coiled tube in the back of the testicles that stores and transports sperm (James, 2020). The contents of the fluid determine whether it’s an epididymal cyst or what’s called a spermatocele. 

These terms are interchangeable because the only difference between the two is the fluid contents. An epididymal cyst contains fluid, and a spermatocele contains seminal fluid and sperm (O’Kelly, 2019). A physical exam or ultrasound can't differentiate the two, and they are both treated the same. 

Typically, these cysts are small and soft, measuring about 2-4 millimeters in size. When they’re that small, you usually can’t even feel them during a self-exam (Valentino, 2011).  However, these cysts can become quite large. In men seeking treatment for their epididymal cysts, the average size was just around 42 millimeters (around 1.6 inches) (Walsh, 2007). That’s about the average size of a testicle. 

Epididymal cysts are benign, and they have nothing to do with cancer (Crawford, 2014). 

Epididymal cysts are usually small, soft, and painless lumps found on the testicles; however, some men do report testicular pain (Crawford, 2014).

Since pain isn’t the primary symptom of epididymal cysts, swelling or pain in the back of the scrotum may be a sign of epididymitis, a result of a bacterial or viral infection. Discomfort and pain while urinating is another common symptom of epididymitis, and medication is required to treat it (McConaghy, 2016).

Inflammation or blockage of the epididymis may lead to an epididymal cyst or a spermatocele (Valentino, 2011). However, the exact cause of and risk factors for developing the cysts are not fully known (O’Kelly, 2019; Weatherly, 2018).

If the cyst is big enough, you might first notice a lump in your testicles upon self-examination at home. Then, a physician-led physical examination and ultrasound are needed to confirm and diagnose the cyst (O’Kelly, 2019; Valentino, 2011). Ultrasounds can also rule out solid growing scrotal masses in the testes (O’Kelly, 2019; Weatherly, 2018). They are now a widespread practice in many clinics. And healthcare providers are now better able to detect epididymal cysts, even the small ones that may evade notice during a physical exam (Weatherly, 2018).  

An epididymal cyst is a common reason, but not the only reason for a lump on your testicle or an enlargement of your scrotum. Other common diagnoses that can cause an enlarged scrotum or lump include: 

• Hydroceles: fluid-filled sacs around the testicle; the fluid does not contain sperm (Dagur, 2017). 

• Varicoceles enlarged or dilated veins in the scrotum, specifically the spermatic cord, that may lead to swelling (Lomboy, 2016). 

While they can be a sign of testicular cancer, in most cases, they’re not. Testicular cancer is a rare and very treatable disease. Only about 9,000 new cases are diagnosed in the U.S. each year (ACS, 2021). 

If a spermatocele doesn’t bother you, you probably don’t need treatment. These cysts usually don’t cause pain and are often not noticed. Treatment is typically only considered when you have symptoms (Pieri, 2003) 

Treatment options for spermatoceles include:

Aspiration

Aspiration involves inserting a needle into the cyst and draining the fluid. In a 2020 study, this non-invasive procedure was able to resolve epididymal cysts in 25 out of the 34 people. They reported that they would be happy to have the procedure again if needed (Low, 2020). 

Even after treatment, epididymal cysts may grow back (Vissamsetti, 2011). However, the researchers of this study explain that recurrence of the cyst is not dependent on how much fluid the cyst initially contains (Low, 2020). 

Sclerotherapy

Sclerotherapy may be used in addition to aspiration, especially if the cyst grows back. Sclerotherapy involves injecting a solution, like alcohol, into the cyst. This is an outpatient procedure with local anesthesia (Low, 2020). 

Surgery

Healthcare providers may occasionally recommend surgery—a spermatocelectomy—where a surgeon makes an incision in the testis and removes the cyst. This procedure requires the use of general anesthesia (Vissamsetti, 2011). Some procedures, including surgery, are becoming more controversial due to complications or side effects like pain (Lundström, 2019; O’Kelly, 2019).

Epididymal cysts are common, and a diagnosis isn’t something to stress about (Weatherly, 2018). Additionally, there is no evidence to suggest that these cysts are associated with infertility (Lundström, 2019; Weatherly, 2018). 

However, finding a lump on your testicle should always be checked out by a physician. While epididymal cysts are benign and healthcare providers can treat them, a proper medical screening can rule out other—potentially more serious—diagnoses of the lump (Valentino, 2011). 

Talk to your physician to see if you should conduct self-exams at home to screen for and monitor any changes in between routine physicals.

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Current version

September 29, 2021

Written by

Molly Knudsen, MS, RDN

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.