A hydrocele is a type of swelling in the scrotum, the pouch of skin that holds the testicles. This swelling happens when fluid collects in the thin sac that surrounds a testicle.
Adults can get a hydrocele due to an injury within the scrotum or other health problems. A hydrocele often isn’t painful or harmful. It might not need any treatment. But it’s important to see a health care professional if the scrotum looks swollen.