A hydrocele is a buildup of fluid around one or both testicles that causes the scrotum or groin area to swell. The swelling may be unsightly or uncomfortable, but it is not painful.

Hydroceles may be present at birth (congenital) or may develop after birth (acquired). Congenital hydroceles usually go away by age 2. Acquired hydroceles may be caused by an injury to the groin area. Or the cause may be unknown. An acquired hydrocele can occur at any age, but it is most common in men older than 40.

If a hydrocele stays the same size or gets smaller as the body reabsorbs the fluid, generally no treatment is needed. If the hydrocele varies in size or gets bigger and becomes uncomfortable, surgery may be needed to remove the fluid.