What is a hydrocele?

A hydrocele (HI-dra-seel) is a fluid-filled sac in your scrotum that causes swelling. Your scrotum is the pouch of skin behind your penis that holds your testes (testicles). A hydrocele may affect one side of your scrotum or both sides. Another name for hydroceles around both of your testicles is a bilateral hydrocele.

Hydroceles can affect anyone assigned male at birth (AMAB), but they’re more common in infants.

They can also occur spontaneously in adulthood.

How serious is a hydrocele?

Hydroceles can be alarming because they cause swelling in a sensitive part of your body and can happen suddenly. In some instances, hydroceles can be bothersome depending on their size. A large hydrocele may cause discomfort while sitting or walking. However, in many people, a hydrocele isn’t serious, bothersome or painful.

What are the types of hydroceles?

There are two types of hydroceles: communicating hydroceles and noncommunicating hydroceles.

Communicating hydrocele

A communicating hydrocele has contact (communication) with the fluids in your abdominal cavity. Your abdominal cavity is the space within your abdomen that contains your stomach, intestines, liver, kidneys and other organs. Communicating hydroceles occur in fetal development.

During development, a thin membrane forms between some tissues in the fetus’s stomach lining (inguinal canal) and the scrotum. This membrane is the processus vaginalis. Normally, the testicles slide (descend) from the abdomen through the processus vaginalis into the scrotum. Tissue then forms to seal the opening (communication). If a seal doesn’t form, fluids from the abdominal cavity can flow into the scrotum and cause a hydrocele or hernia.

If you or your child has a communicating hydrocele, the scrotum will appear large or swollen, and it may change in size throughout the day.

Noncommunicating hydrocele

In a noncommunicating hydrocele, the processus vaginalis closes. But there’s still some extra abdominal fluid around the testicle in the scrotum. Noncommunicating hydroceles may be present at birth or develop years later for no obvious reason.

If you or your child has a noncommunicating hydrocele, it usually remains the same size or grows very slowly.

What are the symptoms of a hydrocele?

The main symptom of a hydrocele is swelling on one or both sides of your scrotum that may feel like a water balloon. You might notice other symptoms in your scrotum, like:

• Swelling that changes in size during the day.
• Discomfort.
• Pain.
• A feeling of heaviness.

Will a hydrocele affect fertility?

Hydroceles usually don’t cause infertility.

What causes a hydrocele?

Infants that have a hydrocele are usually born with it. Hydroceles are typically part of fetal development, when abdominal fluid can flow into the scrotum if the processus vaginalis doesn’t close. And sometimes, even if the processus vaginalis closes, abdominal fluid may remain in the scrotum. Your child’s body usually absorbs this fluid within the first two years.

Who do hydroceles affect?

Hydroceles are much more common in babies and infants, but may also occur in adolescents and adults.

About 10% of newborn infants have a hydrocele, which often clears up without treatment within the first year.

Hydroceles occur in only about 1% of adults. They often disappear on their own without treatment.

What causes a hydrocele in adults?

In older children, teenagers or adults, a hydrocele can form as a result of an injury to or inflammatory infection of the scrotum.

How is a hydrocele diagnosed?

A healthcare provider can diagnose a hydrocele in a child or adult. They’ll ask questions about your symptoms and perform a physical examination.

During the physical exam, the provider may apply pressure to the groin area or ask you to cough to see how the swelling changes. They may shine a light through your scrotum to highlight any abdominal fluid in the area. A provider can diagnose most hydroceles from a physical exam alone.

To confirm their diagnosis, the provider may order imaging tests, including:

• Pelvic ultrasound. A pelvic ultrasound uses high-frequency sound waves to create images of the soft tissues in your pelvis, including your testicles. It’s the most common imaging test providers order for a hydrocele diagnosis.
• Computed tomography (CT) scan. A CT scan is a type of X-ray that takes cross-section pictures of your body — like slices — to create 3D images of your testicles. A CT scan is more precise than a standard X-ray.