Obstetrics - Cystic Hygroma

Introduction

You have been given this leaflet because your baby was found to have a cystic hygroma on a recent pregnancy scan. We hope this will help you to understand more about this condition, and what this means for your pregnancy.

What is a cystic hygroma?

A cystic hygroma is a collection of fluid-filled sacs (cysts) that results from a blockage in the lymphatic system. It is most commonly located in the neck or head area, but can be located anywhere in the body. It is often discovered during early pregnancy, around the time of the dating scan between 11 to 14 weeks.

What causes a cystic hygroma and can it be prevented?

The lymphatic system is a network of vessels within the body which form part of the immune system. They work in a similar way to blood vessels, but instead of carrying blood, they carry lymph fluid around the body.

A cystic hygroma forms when the lymph vessels fail to form correctly during the first few weeks of pregnancy. If this system isn’t working properly the lymph fluid can accumulate (build up) – this is known as a cystic hygroma.

It cannot be prevented as it occurs so early in pregnancy. Nothing you did or did not do during pregnancy caused the cystic hygroma to develop.

How common are cystic hygromas?

They occur in approximately one out of 800 pregnancies, and can affect both males and females of any ethnicity.

What does this mean for my pregnancy?

In about 10% of cases there are no other obvious problems (such as unusual chromosomes) and the cystic hygroma resolves during pregnancy. In these cases the prognosis is good. Sometimes babies are born with a cystic hygroma, visible as a soft lump.  Further treatment (usually removal of the cystic hygroma) is then offered after birth.

However, a cystic hygroma can also be an indicator of other problems with the development of the baby.

These include:

• Chromosomal problems: these are found in about 50% (half) of cases. The most common chromosome problems are Down’s syndrome, Edward’s syndrome, Patau’s syndrome or Turner’s syndrome
• Genetic syndromes: these are found in about 40% of cases. The most common problem is Noonan’s syndrome
• Cardiac (heart) problems: found in approximately 40 to 50% of cases
• Hydrops: this is a condition that occurs when large amounts of fluid build-up in a baby's tissues and organs causing extreme swelling. Hydrops can put additional pressure on the baby’s heart. This occurs in about 60 to 80% of cases of cystic hygroma

Because of the link between cystic hygroma and these problems, there is unfortunately an increased chance of miscarriage.

What happens now?

You will be referred to the Oldham Fetal Medicine Unit, and offered a detailed scan with one of the fetal medicine consultants. The midwives will be in touch with you by telephone to arrange this appointment.

The team will offer and explain any further tests that can be used to help identify the underlying cause of the cystic hygroma, including tests to check the baby’s chromosomes.

Contact details

We understand that this can be a worrying time for you, your partner and your family.

If you have any questions, or need any support please call the Oldham Fetal Medicine Fetal Unit on the details below.

Telephone 0161 778 5183 between 9am to 5pm Monday to Friday.

Acknowledgements

Great Ormond Street NHS Foundation Trust
Birmingham Children’s Hospital NHS Foundation Trust

Further information

Fetal Medicine Foundation
https://fetalmedicine.org/education/fetal-abnormalities/neck/ cystic-hygroma
https://www.gosh.nhs.uk/conditions-and-treatments/conditions- we-treat/cystic-hygroma/