Cystic hygromas are abnormal growths that usually appear on a baby’s neck or head. This disorder most often forms while the baby is still in the womb; however, a hygroma can also appear after birth. Cystic hygromas are fluid-filled sacs caused by blockages in the lymphatic system. They consist of one or more fluid-filled cysts. In general, they get larger over time.
According to Emory University School of Medicine (EUSM), cystic hygromas occur in one percent of fetuses. Usually forming between the ninth and 16th week of pregnancy, approximately half of all fetuses with a hygroma have chromosomal abnormalities. If the hygroma resolves on its own by week 20, and your baby has normal chromosomes, outcomes are usually good. However, if it does not, the fetus could have serious medical complications (EUSM).
Doctors recommend that you schedule your delivery in a major medical center if a hygroma is detected during pregnancy. There is also an increased risk of miscarriage or fetal death.
Cystic hygroma can develop either as part of a genetic syndrome or due to environmental factors. One or more growths may be present at the time of diagnosis.
Common environmental causes of cystic hygromas are:
- viral infections passed from mother to baby during pregnancy
- exposure to drugs or alcohol during pregnancy
Cystic hygromas are seen more often in infants with genetic diseases. They are particularly common in infants with chromosomal abnormalities. Some genetic conditions associated with hygromas include:
- Turner’s Syndrome—where female children have one x chromosome instead of two
- Trisomy 13, 18, or 21—conditions where children have an extra copy of a chromosome
- Noonan Syndrome—a condition causes by a mutation in one of seven particular genes
Cystic hygromas may not be visible when a child is first born. They can appear later, and get larger, as a child grows. Small hygromas are more likely to be discovered as a child gets older. However, most hygromas appear by age 2.
The main symptom of a cystic hygroma is the presence of a soft, non-tender, compressible lump. This lump, the hygroma, most commonly appears on the neck. However, hygromas can appear anywhere on the body where there is lymphatic tissue, such as the armpits or the groin. They can also appear under the skin of the trunk or limbs.
Cystic hygromas range in size from smaller than a quarter to as large as the child’s head. Large growths may interfere with movement or cause other difficulties.
If a doctor notices a cystic hygroma during an ultrasound, he or she will order an amniocentesis. This test can check for genetic abnormalities in your fetus.
During this test, you will lie on an examining table while your doctor cleans your belly with an iodine solution. Using ultrasound as a guide, your doctor will then use a needle to sample fluid from the amniotic sac.
If the cystic hygroma is not discovered until after birth, other tests will be used for diagnosis. These include:
- chest X-ray
- CT scan
While in the womb, cystic hygromas are not treated. Instead, the health of your baby will be closely monitored. You will probably need to schedule your delivery at a major medical center in case there are complications at the time of birth.
If a hygroma is seen on a child after birth, it is usually quite treatable. The first line of treatment is to use surgery to remove the growth. The entire growth must be removed to prevent it from growing back.
Sometimes, it can be difficult or impossible to remove a large hygroma. Since these tumors are most often benign, doctors do not want to risk injuring healthy tissue to get rid of them. In such cases, other techniques may be used to shrink the hygroma. These include:
- sclerotherapy – where irritating material is injected into the cyst to shrink it
- radiation therapy
- steroid medication
Shrinking methods aren’t very effective in treating small cystic hygroma, but they may be useful in shrinking large growths. Once the growth is small enough, it is easier to surgically remove.
Under no circumstance should you attempt to puncture drain a hygroma yourself. They are very susceptible to infection. There is also a risk of severe bleeding.
Hygromas are benign growths. If they appear after birth, outlook is generally good. This is particularly true if the growth can be completely removed. If removal is impossible cystic hygromas may return or spread to other areas.
The main potential complications of cystic hygroma are:
- recurring growths
- infection in the affected area
- damage to muscles, nerves, or tissues from surgery to remove the hygroma