A spermatocele (SPUR-muh-toe-seel) is an abnormal sac (cyst) that develops in the epididymis — the small, coiled tube located on the upper testicle that collects and transports sperm. Noncancerous and generally painless, a spermatocele usually is filled with milky or clear fluid that might contain sperm.
The exact cause of spermatoceles is unknown but might be due to a blockage in one of the tubes that transports sperm.
Spermatoceles, sometimes called spermatic cysts, are common. They typically don't reduce fertility or require treatment. If a spermatocele grows large enough to cause discomfort, your doctor might suggest surgery.