Alternative names
Processus vaginalis; Patent processus vaginalis

A hydrocele is a fluid-filled sack along the spermatic cord within the scrotum.

Causes, incidence, and risk factors

Hydroceles are common in newborn infants. The fluid buildup can be on one or both sides of the scrotum.

During normal development, the testicles descend down a tract (tube) from the abdomen into the scrotum. Hydroceles result when this tube fails to close. Peritoneal fluid drains from the abdomen through the open tube. The fluid accumulates in the scrotum, where it becomes trapped. This causes the scrotum to enlarge.

Hydroceles normally resolve after a few months after birth, but their appearance may worry new parents. Occasionally, a hydrocele may be associated with an inguinal hernia. Hydroceles can be easily demonstrated by shining a flashlight through the enlarged portion of the scrotum. If the scrotum is full of clear fluid, as in a hydrocele, the scrotum will light up (transillumination).

Hydroceles may also be caused by inflammation or trauma of the testicle or epididymis, or by fluid or blood obstruction within the spermatic cord. This type of hydrocele is more common in older men.


The main symptom is a painless, swollen testicle, one or both sides, which feels like a water-filled balloon.

Signs and tests

During a physical exam, the doctor would identify an enlarged scrotum that is usually not tender. Often, the testicle cannot be felt because of the surrounding fluid. The size of the fluid-filled sack can sometimes be increased and decreased by pressure to the abdomen or the scrotum.

If the size of the fluid collection is variable, it is more likely to be associated with an inguinal hernia. The fluid in a hydrocele is usually clear. Therefore, a light can be shined through the scrotum, outlining the testicle and indicating the presence of clear fluid. An ultrasound may be done to confirm the diagnosis.


Hydroceles are usually not dangerous, and they are usually only treated when they cause discomfort or embarrassment, or they get so large that they threaten the testicule’s blood supply.

One option is to remove the fluid in the scrotum with a needle (a process called aspiration). However, aspiration can cause infection, and it is common for the fluid to re-accumulate. Therefore, aspiration is not routine and surgery is generally preferred. On the other hand, aspiration may be the best alternative for people who have certain surgical risks.

Injection of sclerosing (thickening or hardening) medications may be performed after needle aspiration to close off the opening through the scrotal sac. This helps prevent re-accumulation of fluid. The medications include tetracycline, sodium tetradecyl sulfate, or urea. Possible complications after aspiration and sclerosing include infection, fibrosis, mild to moderate pain in the scrotal area, and recurrence of the hydrocele.


Hydrocelectomy is often performed to correct a hydrocele. This is a minor surgical procedure performed on an outpatient basis using general or spinal anesthesia. An incision may be made in the scrotum or the lower abdomen.

The procedure may require a scrotal drainage tube or a large bulky dressing to the scrotal area. You will be advised to wear a scrotal support for some time after surgery. Ice packs should be kept to the area for the first 24 hours after surgery to reduce the swelling in the area.

Possible complications of this procedure include hematoma (blood clot formation), infection, or injury to the scrotal tissue or structures.

Hydroceles associated with an inguinal hernia should be repaired surgically as quickly as possible. Hydroceles that do not resolve spontaneously over a period of months should be evaluated for possible surgery.

Expectations (prognosis)
Generally, a simple hydrocele goes away without intervention. If surgery is necessary, it is a simple procedure for a skilled surgeon and usually has an excellent outcome.


  • The presence of an inguinal hernia requires surgery.  
  • Possible complications of surgery to correct a hydrocele include, but are not limited to, blood clot formation, infection, or injury to the scrotal tissue or structures.  
  • Possible complications after aspiration and sclerosing include, but are not limited to, infection, fibrosis, mild to moderate pain in the scrotal area, and recurrence of the hydrocele.

Calling your health care provider

Call for an appointment with your health care provider if you have symptoms of hydrocele (to rule out other causes of a testicle lump).

Acute pain in the scrotum or testicles is a surgical emergency. If enlargement of the scrotum is associated with acute pain, seek medical attention immediately.

Johns Hopkins patient information

Last revised: December 5, 2012
by David A. Scott, M.D.

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