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A hydrocele is a fluid-filled sac in the scrotum.


Hydroceles are common in newborn infants.

During a baby's development in the womb, the testicles descend from the abdomen through a tube into the scrotum. Hydroceles occur when this tube does not close. Fluid drains from the abdomen through the open tube and gets trapped in the scrotum. This causes the scrotum to swell.

Most hydroceles go away a few months after birth. Sometimes, a hydrocele may occur with an inguinal hernia.

Hydroceles may also be caused by:

  • Buildup of the normal fluid around the testicle. This may occur because the body makes too much of the fluid or it does not drain well. (This type of hydrocele is more common in older men.)
  • Swelling or injury of the testicle or epididymis


The main symptom is a painless, round-oval shaped swollen testicle, which feels like a water balloon. A hydrocele may occur on one or both sides. However, the right side is more commonly involved. 

Exams and Tests

You will have a physical exam. The health care provider will find that the scrotum is swollen, but not painful to the touch. Often, the testicle cannot be felt because of the fluid around it. The size of the fluid-filled sac can sometimes be increased and decreased by putting pressure on the abdomen or the scrotum.

If the size of the fluid collection changes, it is more likely to be due to an inguinal hernia.

Hydroceles can be easily seen by shining a flashlight through the swollen part of the scrotum. If the scrotum is full of clear fluid, the scrotum will light up.

You may need an ultrasound or CT scan to confirm the diagnosis.


Hydroceles are not harmful most of the time. They are treated only when they cause infection or discomfort.

Hydroceles from an inguinal hernia should be fixed with surgery as soon as possible. Hydroceles that do not go away on their own after a few months may need surgery. A surgical procedure called a hydrocelectomy (removal of sac lining) is often done to correct the problem. Needle drainage does not work well because the fluid will come back.

Outlook (Prognosis)

Simple hydroceles in children often go away without surgery. In adults, hydroceles usually do not go away on their own. If surgery is needed, it is an easy procedure with very good outcomes.

Possible Complications

Risks from hydrocele surgery may include:

  • Blood clots
  • Infection
  • Injury to the scrotum
  • Loss of the testicle
  • Long-term (chronic) pain
  • Continuous swelling

When to Contact a Medical Professional

Call your provider if you have symptoms of hydrocele. It is important to rule out other causes of a testicular lump.

Pain in the scrotum or testicles is an emergency. If you have pain and your scrotum is enlarged, seek medical help right away to prevent the loss of the testicle.

Alternative Names

Processus vaginalis; Patent processus vaginalis


Aiken JJ, Oldham KT. Inguinal hernias. In: Kleigman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 346.

Elder JS. Disorders and anomalies of the scrotal contents. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 545.

Ferri FF. Hydrocele. In: Ferri FF, ed. Ferri's Clinical Advisor 2018. Philadelphia, PA: Elsevier; 2018:640-640.

Germann CA, Holmes JA. Selected urologic disorders. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 89.

Katz A, Richardson W. Surgery. In: Zitelli BJ, McIntire SC, Nowalk AJ, eds. Zitelli and Davis' Atlas of Pediatric Physical Diagnosis. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 18.

Palmer LS, Palmer JS. Management of abnormalities of the external genitalia in boys. In: Wein AJ, Kavoussi LR, Partin AW, Peters CA, eds. Campbell-Walsh Urology. 11th ed. Philadelphia, PA: Elsevier; 2016:chap 146.

Review Date 8/26/2017

Updated by: Jennifer Sobol, DO, urologist with the Michigan Institute of Urology, West Bloomfield, MI. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.