Causes Of Cystic Hygroma, Its Signs, Diagnosis, And Treatment

Most causes are not preventable, and surgery is usually done.

Written by Dr Bisny T. Joseph • 

Cystic hygroma refers to overgrowth on the head or neck. Cystic hygroma in babies is present from birth and usually becomes visible as the baby grows. It can be either one or multiple cysts.

The cyst develops from developmental irregularity in the lymphoid system when the baby is still a fetus. The reason behind this may be a chromosomal abnormality or other birth malformations. The symptoms may vary depending on the location and size of the cyst. Adverse outcomes can be obstruction of the airway or failure to thrive.

Read on to know about cystic hygromas in babies, including their causes, symptoms, complications, and treatments.

Causes Of Cystic Hygroma

Abnormalities of lymph vessels and lymph sacs during fetal development may cause a cystic hygroma to form. The cysts are formed by blockages in embryonic lymphatic tissue, which carries fluid and white blood cells through the body.

Some babies may have a cystic hygroma without any known reason. Cystic hygromas may be associated with various chromosomal abnormalities and other conditions that include the following (1).

  • Turner syndrome is a genetic anomaly in females due to a complete or partial lack of the X chromosome.
  • Noonan syndrome is a genetic condition with abnormalities of various parts of the body including facial structure, heart, stature, and development.
  • Down syndrome or trisomy 21 is a chromosomal anomaly with mental and physical developmental delay concerns.
  • Maternal viral infections during pregnancy may cause abnormalities of development.
  • Maternal alcohol use may also affect the development of the fetus.

Some fetuses with normal chromosomes may have a cystic hygroma on the 10th-week ultrasound, and it may disappear by the 20th week. In comparison, there is a high chance for a cystic hygroma to persist if the baby has chromosomal abnormalities.

Symptoms Of Cystic Hygroma

The symptoms may vary based on the size of the cystic hygroma. Visible neck growth is the most common symptom of cystic hygroma in babies. Some babies may not have any symptoms other than a visible lump, while a few may have respiratory and feeding problems due to obstruction. Teeth malformations may also occur in older babies.

The cyst is usually a translucent, fluid-filled, and painless soft lump. It is most common on the neck but may occur anywhere on the body. It may be visible at birth in some babies as a soft bulge under the skin (2).

Cystic hygromas may go unnoticed in a few babies and are often visible after they grow older or after a bout of an upper respiratory tract infection, such as the common cold. It is recommended to seek medical attention if you notice growth or bulges on your baby’s neck.

Diagnosis Of Cystic Hygroma

Cystic hygromas may be visible on prenatal ultrasound in some cases. Increased neck thickness and fluid in the backside of the neck on ultrasound may indicate this condition (3).

The following tests are often done to examine cystic hygromas in babies after birth.

  • Ultrasound
  • Chest X-ray
  • CT scan
  • MRI scan

If the condition is noted on a pregnancy ultrasound, gynecologists may order amniocentesis and genetic testing since cystic hygromas may be associated with certain genetic disorders and birth defects. Maternal and fetal blood may also have increased levels of alpha-fetoprotein (AFP) in most cases. 

Treatment For Cystic Hygroma

Surgical removal of the cystic hygroma is often performed since the success of other treatment options is limited. However, other treatments are usually given when the complete removal of the cystic hygroma is impossible. These treatment modalities may include the following (4).

  • Radiation therapy may help to prevent the growth of the cyst. However, the recurrence rate within a year is high among babies who undergo radiotherapy.
  • Chemotherapy with drugs such as Bleomycin may cause fibrosis of the cyst due to inflammation and prevent its growth.
  • Steroids may help to shrink large growths.
  • Sclerotherapy uses an injection of sclerosing medications to shrink the lymphatic vessels within the cystic hygroma. This procedure is considered safe, although there is some risk of bleeding and infection at the injection site.

A cystic hygroma should only be drained or treated by a physician due to the risk for bleeding, infection, or other complications pertinent to its location.

Possible Complication Of Cystic Hygroma

The following complications are often seen in some babies with cystic hygromas (5).

  • Bleeding
  • Infection
  • Recurrence after removal
  • Damage of neck structures during surgery
  • Obstructive sleep apnea
  • Feeding and respiratory difficulties

Babies with larger cystic hygromas during the fetal period may require cesarean delivery since it may be impossible for them to pass through the birth canal.

Prognosis Of Cystic Hygroma

A small cystic hygroma is more likely to resolve itself without causing any complications (5). However, cystic hygroma can often grow bigger than the size of the head in some babies. Extensive growth may affect the normal functioning of neck structures and neck movement.

The prognosis is good if the entire hygroma can be removed surgically. If the abnormal tissue is not obliterated, it may grow again and re-form the hygroma. Hygromas also have a better prognosis if it appears after birth. The long-term outcome may also depend on chromosomal anomalies, birth defects, and other coexisting factors.

Prevention of cystic hygromas may not be possible since they are most often diagnosed on the first fetal ultrasound. A cystic hygroma is a manageable condition with proper and timely treatment. You may discuss with the pediatrician to know the suitable treatment for your baby based on the size and location of the growth.

Frequently Asked Questions

1. Can a baby survive with cystic hygroma?

If cystic hygroma is treated properly, then the outlook is good. However, long-term outcomes may depend on the size of the hygroma and its location (6).

2. How common is fetal cystic hygroma?

Cystic hygroma is a rare condition that makes up about 6% of all benign lesions in newborns and young children (7). And in some cases, it could lead to congenital disabilities.

3. Does cystic hygroma mean Down syndrome?

No, cystic hygroma does not mean Down syndrome, but the condition may be associated with Down’s syndrome. Chromosomal abnormality that causes Down syndrome may also cause cystic hygroma (8).

Cystic hygroma in babies is a congenital abnormality that cannot be prevented. However, one can manage the condition with prompt diagnosis and treatment. The treatment of cystic hygroma usually depends on its size, the location of the growth, and co-existing factors. A small hygroma mostly resolves itself without any complications. However, a large hygroma would require medical intervention to avert the risk of adverse complications, such as bleeding, infection, obstructive sleep apnea, and feeding difficulties. Fortunately, the prognosis of cystic hygroma is good if the entire sac is removed.

Key Pointers

  • Cystic hygroma is caused by abnormal development of lymph vessels and sacs, causing a blockage in lymphatic tissue during fetal life.
  • Cystic hygroma growth can be visible on the neck. The severity of other signs such as respiratory obstruction and feeding issues may vary depending on the size of the growth.
  • It is often surgically removed, and other treatments such as radiation or chemotherapy are given if surgery is contraindicated.


1. Cystic Hygroma; U.S. Department of Health and Human Services
2. Cystic Hygroma; Sakra World Hospital
3. Cystic Hygroma; National Health Service
4. Cystic Hygroma; Johns Hopkins Medicine
5. Cystic Hygroma; MedlinePlus; U.S. National Library of Medicine
6. Cystic Hygroma Great Ormond Street Hospital for Children
7. Nadja Auerbach et al.; Cystic Hygroma National Library of Medicine
8. Cystic Hygroma Monroe Carell Jr. Children’s Hospital, Vanderbilt
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