Cystic hygromas are fluid-filled sacs that occur most commonly on the head or neck of a baby. They are a result of blockages in the lymphatic system.
Doctors can sometimes detect cystic hygromas using ultrasounds during pregnancy. They can also diagnose them after the baby is born. Some cystic hygromas may not appear until the child is a bit older.
In this article, learn more about the causes and symptoms of cystic hygromas, as well as the treatment options.
According to The Fetal Medicine Foundation, cystic hygromas affect 1 in 800 pregnancies and 1 in 8,000 live births.
In 80 percent of cases, cystic hygromas appear on the face, including the head, neck, mouth, cheek, or tongue.
The growths can also occur in other areas of the body, including the armpits, chest, legs, buttocks, and groin. There may be one more than one growth, which can also grow over time.
Cystic hygromas that are present at birth or develop after birth are usually benign, meaning they are not harmful. However, they can be disfiguring, grow to be very large, and affect a child’s breathing and ability to swallow.
Sometimes, cystic hygromas detected early in pregnancy go away before birth. A fetal cystic hygroma can be a risk factor for miscarriage.
Cystic hygromas usually affect children, but there have been rare cases of them appearing in adulthood.
A 2016 case study reported on a 32-year-old man with a cystic hygroma on his neck. The hygroma appeared 8 months before diagnosis.
The man was experiencing pain and swelling in the right lower region of his face extending to his neck. Doctors took a biopsy and were able to confirm that it was adult-onset cystic hygroma.
Both environmental and genetic factors can contribute to the formation of cystic hygromas. Causes may include:
- viral infections passed to a fetus during pregnancy
- drug or alcohol use during pregnancy
More often, cystic hygromas are due to genetic conditions. In fact, chromosomal abnormalities account for 50 percent of cases.
Genetic conditions that cause cystic hygromas include:
- Turner syndrome: Turner syndrome is a condition where a woman is wholly or partially missing an X chromosome. It can cause changes in appearance, and problems with the heart and fertility.
- Noonan syndrome: People with Noonan syndrome may have unusual facial features, short stature, heart issues, bleeding problems, skeletal abnormalities, and many other symptoms.
- Trisomy 13, 18, or 21: These conditions cause a fetus to develop an extra set of chromosomes, which produce a variety of congenital abnormalities, including intellectual disability.
Cystic hygromas can also occur without a known cause.
Symptoms of a cystic hygroma vary depending on the location of the cysts. Some children may not experience any symptoms other than the growth.
If a child has symptoms, they may include:
- fluid-filled sacs on the tongue
- large cysts that appear blue
- obstructive sleep apnea, a sleep disorder that causes breathing to stop and start
- breathing and feeding difficulties
- failure to thrive
- bone and teeth abnormalities
In rare cases, the hygromas may bleed or become infected.
Doctors usually diagnose cystic hygromas when the fetus is still in the womb, often during a routine abdominal ultrasound.
Doctors may also detect it during a blood test carried out at 15 to 20 weeks. If the blood test shows high levels of alpha-fetoproteins, it might indicate a possible cystic hygroma.
Ultrasound images may indicate the possible location and size of a cystic hygroma, but doctors will require more information. They will want to know the depth and severity of the growth and if there are any obstructions, including those that could indicate breathing problems.
Doctors may do additional tests, including:
- Transvaginal ultrasound: A transvaginal ultrasound can take better images of the cystic hygroma without other organs in the way.
- Fast spin magnetic resonance imaging (MRI): A fast spin MRI can provide a clear image and more details about the cystic hygroma. Unfortunately, it is an expensive test.
- Amniocentesis: During amniocentesis, a doctor will collect amniotic fluid through a special needle, then test it for chromosomal abnormalities.
A doctor will use computed tomography (CT) scans, X-rays, and ultrasounds to make a diagnosis if they find a cystic hygroma after a child is born.
A cystic hygroma might not need treatment if it is not causing any problems.
One treatment option is sclerotherapy. During sclerotherapy, a specialist injects a chemotherapeutic agent called bleomycin into the growth.
Bleomycin shrinks the growth, although it may take several therapy sessions for this to happen. A cystic hygroma can also grow back.
A doctor may consider surgery to remove the cystic hygroma, but will often wait until the child is a bit older. Surgery can cause significant scarring.
Possible complications of surgical removal include damage to nerves, arteries, blood vessels, and structures near the cystic hygroma.
Both sclerotherapy and surgery are performed under general anesthesia, meaning the individual will be asleep and unable to feel pain during the procedure.
In some cases, a baby or child may need both treatments to remove or shrink the cystic hygroma completely.
The long-term outlook for cystic hygromas depends on the size and location of the growth.
Some cases of cystic hygromas have associations with other genetic conditions that may impact a child’s development.
Cystic hygromas can return even after treatment or multiple treatments, especially if doctors cannot remove all the tissue.