The normal scrotum and testes

The scrotum is normally loose, soft and fleshy. It holds the two testicles (testes). Usually you can easily feel the testes in the scrotum. A tube (the vas deferens) takes sperm from each testicle (testis) to the penis. It is normal for one testis to hang lower than the other.

A hydrocele is a collection of fluid in a sac in the scrotum next to a testicle (testis). It usually occurs on one side but sometimes a hydrocele forms over both testicles (testes). It is common in newborns.

Diagram of a hydrocele

The normal testis is surrounded by a smooth protective tissue sac. You cannot normally feel this. It makes a small amount of 'lubricating' fluid to allow the testis to move freely. Excess fluid normally drains away into the veins in the scrotum. If the balance is altered between the amount of fluid that is made and the amount that is drained, some fluid accumulates as a hydrocele.

A hydrocele feels like a small fluid-filled balloon inside the scrotum. It feels smooth and is mainly in front of one of the testicles (testes). They can vary in size. Hydroceles are normally painless. Sometimes fluid can move back and forth between the hydrocele and the abdominal cavity - this is called a communicating hydrocele and you might see swelling that appears to move between the tummy (abdomen) and the scrotum. Another type of hydrocele is called non-communicating, where the fluid stays in the scrotum. There may be no hydrocele symptoms - your baby is unlikely to be in pain - but you might notice an apparent lump or swelling in the scrotum.

Some babies are born with a hydrocele. Hydroceles are very common in babies. When babies develop in the womb (uterus), the development of the testicles (testes) sees the testicles move from the tummy (abdomen) to the scrotum. Sometimes the passage which allows this to happen (the processus vaginalis) does not close completely. This may then lead to a hydrocele developing.

Hydroceles can sometimes be associated with an inguinal ernia, which occurs when part of the intestine pushes through a weak spot in the muscles of the abdominal wall.

In older children a hydrocele may have other causes such as injury, torsione del testicolo oppure sindrome nefrotica.

The diagnosis of hydrocele can normally be made by history and examination. If there is doubt about the nature of the scrotal lump, an ultrasound may be needed.

Hydroceles usually improve without any treatment within the first year of life. An operation is usually only advised if the hydrocele persists after 12-24 months of age.

If your child also has a hernia, often seen as a lump in the groin area, then this will usually be corrected in the same operation.

The operation for a hydrocele involves making a very small incision (cut) in the lower tummy (abdomen) or the scrotum. Sometimes the procedure is done by keyhole surgery (laparoscopically). The fluid is then drained from around the testicle (testis). The passage between the abdomen and the scrotum will also be sealed off so the fluid cannot reform in the future. This is a minor operation and is performed as a day case, so does not usually involve an overnight stay in the hospital.

There are no long-term effects of having a hydrocele. Having a hydrocele does not affect the testicles (testes) or a boy's ability to have children in the future.