Condition Basics

What is a spermatocele?

A spermatocele (epididymal cyst) is a painless, fluid-filled cyst in the long, tightly coiled tube that lies above and behind each testicle (epididymis). The fluid in the cyst may contain sperm that are no longer alive. It feels like a smooth, firm lump in the scrotum on top of the testicle.

Having a spermatocele doesn't affect a man's fertility.

What causes it?

Although the cause of a spermatocele is often unknown, it may be caused by obstruction of the tubes that carry sperm from the testicles (epididymal ducts).

What are the symptoms?

Often a spermatocele does not cause symptoms. You may notice what looks or feels like an extra lump or mass above the testicle on one side of your scrotum. Or you may notice a general enlargement of your scrotum. Symptoms, when present, can include pain, swelling, or redness of the scrotum or a feeling of pressure at the base of the penis.

How is it diagnosed?

A spermatocele is usually diagnosed by examining the scrotum. As part of the examination, your doctor will shine a light behind each testicle (transillumination) to check for solid masses that may be caused by other problems, such as cancer of the testicle. Spermatoceles are filled with fluid, so light will shine through them (transillumination). Light will not pass through solid masses that may be caused by other problems, such as cancer of the testicle. An ultrasound may be used to confirm the diagnosis of a spermatocele.

Spermatoceles are not usually dangerous and are treated only when they cause pain or embarrassment or when they decrease the blood supply to the penis (rare). Treatment is not usually needed if a spermatocele does not change in size or gets smaller as the body reabsorbs the fluid.

If the spermatocele gets larger or causes discomfort, a procedure to remove the spermatocele (spermatocelectomy) may be needed.