Hydrocele in Men: Causes, Symptoms, Diagnosis & Treatment

A hydrocele is a buildup of fluid in the thin sac surrounding a testicle, causing swelling in the scrotum. It is usually painless and may develop gradually, so some men notice only that one side of the scrotum has become larger or heavier.

A hydrocele may occur on one or both sides, and the swelling may stay small or gradually become quite large.

In adults, possible causes include inflammation or infection (such as epididymitis or orchitis), injury to the scrotum, surgery involving the groin or scrotum, or a fluid imbalance where the membranes around the testicle produce more fluid than the body absorbs. In many cases no specific cause is found — this is called an idiopathic hydrocele.

In children, a hydrocele can occur when a passage between the abdomen and scrotum fails to close properly after development.

The most noticeable symptom is usually painless swelling of the scrotum, with possible heaviness, tightness, or mild discomfort when the hydrocele is large.

A hydrocele itself usually does not cause severe pain. Significant pain, redness, fever, or sudden swelling suggests another condition may be present and requires urgent medical evaluation.

A hydrocele is caused by fluid accumulating around the testicle, while a varicocele involves enlarged veins in the scrotum. The two can sometimes occur together but are diagnosed and treated differently.

A hydrocele usually feels like a smooth fluid-filled swelling, while a varicocele may feel more like enlarged or twisted veins. A doctor can distinguish between them through examination and, when necessary, ultrasound.

A urologist usually begins with a medical history and physical examination, assessing the size of the swelling, whether it is painful, whether the testicle can be felt separately, and whether there are signs of infection, hernia, or varicocele.

A scrotal ultrasound is commonly used when the diagnosis is uncertain or the testicle cannot be adequately examined because of the swelling.

A small hydrocele that causes no symptoms may not require immediate treatment — observation may be enough.

For a persistent, large, or symptomatic hydrocele, the main definitive treatment is usually hydrocelectomy, in which the surgeon removes or closes the fluid-filled sac. Aspiration with a needle can temporarily reduce the size, but fluid often returns, so it is generally not considered a definitive treatment on its own.

See a urologist for new scrotal swelling, one side becoming significantly larger, persistent heaviness, a lump, or increasing discomfort. Seek urgent care for sudden severe pain, rapid enlargement, nausea, vomiting, or fever — these may indicate testicular torsion or another urgent problem.

Does it affect fertility or erections? Usually not — a simple hydrocele does not directly affect fertility, testosterone, or erectile function. Can it become cancer? A hydrocele itself is not a cancer, though fluid can make examining the testicle harder, which is why ultrasound may be recommended. Can it return after surgery? Recurrence is possible but generally uncommon.