Cystic Hygroma: Ultrasound, Symptoms at Birth, Removal

Why This Is a High-Risk Pregnancy and How Babies Grow Up

Cystic hygroma is a type of lymphangioma (a tumor that grows in your lymph system). Your lymph system is a network of vessels that helps balance fluid levels in your blood. It also moves fats and cells that fight disease.

A cystic hygroma occurs as a soft fluid-filled lump on a baby's head. It can be seen on an ultrasound at the end of the first trimester of pregnancy. It often grows in cavities within the neck but can also occur on the skin, or within the chest and belly.

This growth forms when fluid gathers in the two lymph sacs at the back of the fetus's neck or in other places. These sacs should connect with blood vessels so they can return the lymph fluid to your blood. In a faulty lymph system, they do not connect. This lets fluid collect in the lymph sacs, where a lump forms.

Carrying a fetus with cystic hygroma is considered a high-risk pregnancy because of its link with certain congenital (present at birth) malformations and genetic syndromes. Based on its location, the lesion can also cause certain problems that make it hard for your baby to breathe.

This article discusses cystic hygroma diagnosis, prognosis, and treatment. It also describes how a high-risk pregnancy with this problem is observed.

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Cystic hygroma is often found on a routine 12-week ultrasound, though it can be identified as early as 10 weeks of pregnancy. The condition may appear as excess fluid behind the neck of the fetus.

If your fetus has a positive cystic hygroma ultrasound, you will likely have a blood test to measure the level of alpha-fetoprotein in your blood. A high alpha-fetoprotein level in a pregnant person's blood could indicate a cystic hygroma. This test is usually done between the 15th and 20th weeks of pregnancy.

When a cystic hygroma is diagnosed, you will likely have follow-up ultrasounds at least every four weeks during your pregnancy. These scans can help your healthcare provider monitor the growth of the lump and evaluate your fetus for the presence of hydrops fetalis (a collection of fluid in more than one area of the body of a fetus or newborn).

When a cystic hygroma occurs, you may also be sent for one or more of the following tests during your pregnancy:

Prenatal genetic testing to check for genetic or chromosomal conditions:

Specialty ultrasounds that check for congenital conditions that commonly occur with a cystic hygroma:

A cystic hygroma is usually diagnosed during pregnancy, at birth, or shortly after birth. Between 80% and 90% of cases are diagnosed before age 2.

While a cystic hygroma can occur later in childhood and into adulthood, it is rare. When diagnosed later in life, a cystic hygroma is more likely to be confused with other conditions that cause neck swellings in adults, such as the following:

Symptoms of a cystic hygroma that appear after infancy can include the following based on the size and location of the lesion:

In some cases, cystic hygroma can go away without treatment. If genetic testing does not indicate chromosomal abnormalities and no other problems occur later in pregnancy, fluid accumulation can sometimes clear without treatment. This occurs in about 10% of cases.

It is more likely for a cystic hygroma to clear on its own in cases that are not considered severe. These types of cases are likely to involve a small cystic hygroma found before 14 weeks gestation.

A fetus's chances for survival increase when a cystic hygroma resolves. However, that does not affect the fetus's chances of having other congenital malformations, chromosome conditions, or genetic syndromes commonly linked with cystic hygroma formation. Even though a baby's cystic hygroma goes away on its own, other medical problems may still exist.

While cystic hygromas usually are benign (noncancerous), they can become a life-threatening condition if they grow in a position on the baby's neck that blocks the airway and interferes with normal breathing.

When diagnosed in a fetus, cystic hygroma is often severe and can have a prognosis of up to 90% fatality. This prognosis improves if there are no other diagnosed defects.

Having a fetus with a cystic hygroma will mean that you have a high-risk pregnancy (a pregnancy or delivery with increased health risks for the pregnant person, fetus, or both) due to the following problems:

Chromosomal abnormalities are present in 50% of babies with cystic hygroma. The following conditions occur most commonly:

The development of cystic hygroma is believed to occur at the same time that chromosomal abnormalities affect fetal development. These chromosomal conditions, such as Down syndrome and Turner syndrome, increase the risk of having a miscarriage or stillbirth because they are also linked to malformations in the fetus's heart and other organs.

Babies with cystic hygroma are more likely to have congenital malformations. These occur in about 44% of fetuses with abnormal chromosomes and between 13% and 29% of fetuses with normal chromosomes.

The most common areas affected include the following:

Having one of over 6,000 known genetic syndromes (diseases that run in families) can increase your baby's risk of having a cystic hygroma. These rare conditions can be difficult to diagnose before a baby is born.

A cystic hygroma can interfere with the formation of a connection between the lymph system and the blood vessels. If this connection doesn't happen, hydrops fetalis can develop in the fetus and lead to miscarriage or a stillbirth.

Cystic hygroma treatment can't be performed before birth. If this condition is discovered during your pregnancy, you will be advised to give birth at a hospital with access to a neonatal intensive care unit (NICU). The cystic hygroma will be evaluated when your baby is born.

A neonatologist (a physician specializing in treating critically ill newborns) will recommend the need and timing for treatment based on the size and location of the cystic hygroma. Other medical conditions present at birth may also affect the need for treatment.

Cystic hygromas with the following characteristics may require that your newborn receive treatment as soon as possible after birth to prevent further complications:

Cystic hygroma removal via surgery is regarded as the "gold-standard" treatment for this condition. This is the most reliable way to remove all the abnormal tissue.

Cystic hygromas are benign lesions that can remain asymptomatic for long periods. The need for treatment is usually indicated based on one of the following characteristics:

While surgery is the most efficient way to remove the abnormal tissue, cystic hygroma can recur in 20% of treated cases. Even when successful, surgery can include complications involving damage to the baby's airway, facial nerves, and blood vessels.

Other therapies may vary based on the following factors:

Additional treatments may include the following:

Living with a cystic hygroma can vary by individual. Long-term outcomes and complications vary based on the presence of chromosomal abnormalities, congenital malformations, or other genetic conditions that are common with this ailment.

The outlook for babies with cystic hygroma is good when all abnormal tissue is totally removed. When the entire cystic hygroma is not removed, the lesion is likely to recur.

If your child is diagnosed with cystic hygroma and receives appropriate treatment, they can have a normal life span. However, based on the extent and location of a cystic hygroma, your baby may have to deal with the following challenges even after it is removed:

You may benefit from investigating support, patient education, and other resources available from the following groups:

A cystic hygroma is a congenital malformation that forms in the head and neck area of a fetus. It occurs when flaws in your lymph system prevent the lymph sacs from joining with blood vessels. The result allows fluid to collect in the lymph sacs, where lumps form.

Though benign, these lumps can hinder normal breathing if they grow large enough to exert pressure on the airways. They are also linked with certain congenital, genetic, and chromosomal conditions that can increase other problems for your baby.

These fluid-filled lumps are often found during the early stages of pregnancy. While treatment must wait until the baby's birth, the problem can be observed with ultrasound and blood tests. Knowing your fetus has this problem can help your healthcare provider manage your high-risk pregnancy.

Treatment often involves surgery to remove the entire lump. Other treatments may also be used to ensure all tissue and fluid are removed.

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By Anna GiorgiAnna Zernone Giorgi is a writer who specializes in health and lifestyle topics. Her experience includes over 25 years of writing on health and wellness-related subjects for consumers and medical professionals, in addition to holding positions in healthcare communications.