Cystic hygroma

This information sheet explains about cystic hygromas, how they can be treated and what can happen when a child comes to Great Ormond Street Hospital (GOSH).

A cystic hygroma is a collection fluid-filled sacs known as cysts that result from a malformation in the lymphatic system. A cystic hygroma is also known as a lymphatic malformation. The lymphatic system is a network of vessels within the body which form part of the immune system. Lymph nodes are located in the neck, armpits and groin areas and filter the lymph fluid.

Cystic hygromas can develop anywhere in the body, but are commonly found in the neck and armpits. It appears as a painless soft lump, which may be translucent.

A cystic hygroma forms when the lymph vessels fail to form correctly during the first few weeks of pregnancy. It cannot be prevented as it occurs so early in pregnancy, usually before the pregnancy is confirmed.

Nothing done or not done during pregnancy causes the cystic hygroma to develop. The exact cause of cystic hygromas is not clear. They occur in approximately one per cent of children and can affect children of any race and both boys and girls.

Cystic hygromas may be seen on scans during pregnancy. Many cystic hygromas are visible at birth or in early infancy, with almost all being diagnosed by the time a child is two years old.

If the cystic hygroma is in a location where it may be interfering with other tissues and structures, scans such as ultrasound or magnetic resonance imaging (MRI), may be needed.

Treatment may be needed if the cystic hygroma starts to interfere with breathing or feeding as the cysts fill with fluid and swell or if infection develops.

Sometimes cystic hygromas do not need to be treated. For babies, where the cystic hygroma is causing functional problems, the treatment options include surgical removal or injection sclerotherapy. Later in childhood, cosmetic surgery may be discussed either to remove the cystic hygroma or to improve any scarring from an earlier procedure.

• Surgical removal: Detailed scans will be needed to plan the operation and it will only be carried out if the surgeon is confident that the operation will be beneficial. There will be an amount of scarring after the operation, as with all surgery.
• „„Sclerotherapy: This is a procedure carried out by a doctor who specialises in interventional radiology, who injects a medicine into the cysts. The medicine causes an inflammatory reaction, which makes the cystic hygroma shrink. It may take several sclerotherapy sessions for the cystic hygroma to be completely treated and even then, it might grow again. For more information about sclerotherapy, please see our information on lymphatic sclerotherapy.

Every procedure carries some risk of infection and bleeding. Every anaesthetic carries a risk, but this is very small. Modern anaesthetics are very safe and your child’s anaesthetist is a very experienced doctor who is trained to deal with any complications.

With surgical removal and sclerotherapy, there is a small chance of damage to the structures surrounding the cystic hygroma. This is why detailed imaging scans are carried out before the operation. There is a chance that the child could have an allergic reaction to the medicine injected, so families should tell us if their child has had any reactions to medicines in the past.

Even after the cystic hygroma has been removed or shrunk, there is a chance that it could return. Treatment can be repeated if needed.

The family and child will receive a phone call before the procedure is scheduled. The purpose of this is to check that the child is well enough for the procedure and to provide information about what will happen during their stay. On admission they meet the surgeon again and ask any questions they might have. At this appointment we ask for permission for the operation through the signing of a consent form.

After the procedure, the child returns to the ward to wake up fully from the anaesthetic. After surgery, the wound area is covered with a dressing to protect it and a drain may be in place for the first few days then removed. Children usually stay in hospital for two to three nights after surgical removal. Sclerotherapy is usually carried out as a day case procedure.

„„The child should be given pain relief medicines such as paracetamol or ibuprofen according to the instructions on the bottle.

„„The child will go home with a one-week course of oral antibiotics, and asked to follow the instructions on the bottle.

„„The child should avoid rough and tumble play and sports until the area has healed. Swimming should be avoided until after the check up outpatient appointment.

„„The child will need to come back to the hospital for a check up appointment two to four weeks after the operation. We send details of this appointment in the post.

The family should call Peter Pan Ward if:

• „„The child has a temperature of more than 37.5°C.
• „„The operation site is oozing, red or feels hotter than the surrounding skin.
• „„the child is in a lot of pain and pain relief does not seem to help.

The outlook is generally good, although the size and location of the cystic hygroma can influence long term outcomes. As explained above, cystic hygromas can come back after treatment, which would require another operation or sclerotherapy procedure.