A cystic hygroma is a growth that often occurs in the head and neck area. It is a birth defect and is the most common form of lymphangioma. It contains large cyst like cavities containing watery fluid. Microscopically cystic hygroma consists of multiple locules filled with lymph. In the depth the locules are quite big but they decrease in size towards the surface.
Cystic hygromas are benign, but can be disfiguring. It is a condition which affects children; very rarely it can present in adulthood.
Cystic hygroma, is also known as, lymphatic malformation. Nowadays, the medical field prefers to use the term lymphatic malformation because the term cystic hygroma means water tumor. Lymphatic malformation is more commonly used now because it is a sponge-like collection of abnormal growth that contains clear lymphatic fluid. The fluid collects within the cysts or channels, usually in the soft tissue. Cystic hygromas are filled with lymph which is the fluid that travels in the lymphatic system of the body. Cystic hygromas occur when the lymph vessels that make up the lymphatic system aren’t formed properly.
There are two types of lymphatic malformations. They are macrocystic lymphatic malformations (large cysts) and microcystic (small cysts). A person may have only one kind of the malformation or can have a mixture of both macro and micro cysts.
Cystic hygroma can be associated with a nuchal lymphangioma or a fetal hydrops. Additionally, it can be associated with Turner syndrome or with Noonan’s syndrome.
A lethal version of this condition is known as Cowchock Wapner Kurtz syndrome that in addition to cystic hygroma, includes lymphedema and cleft palate.
Causes, incidence, and risk factors
After birth, a cystic hygroma usually looks like a soft bulge under the skin. The cyst may not be found at birth. It typically grows as the child grows. Sometimes it is not noticed until the child is older.
A common symptom is a neck growth. It may be found at birth, or discovered later in an infant after an upper respiratory tract infection.
Signs and tests
Sometimes, a cystic hygroma is seen when the baby is still in the womb using a pregnancy ultrasound. This can mean that the baby has a chromosomal problem or other birth defects.
The following tests may be done:
- Chest x-ray
- CT scan
If the cystic hygroma is detected during a pregnancy ultrasound, other ultrasound tests or amniocentesis may be recommended.
A baby with a prenatally diagnosed cystic hygroma should be delivered in a major medical center equipped to deal with neonatal complications. An obstetrician usually decides the method of delivery. If the cystic hygroma is large, a cesarean section may be performed. After birth, infants with persistent cystic hygroma must be monitored for airway obstruction. A thin needle may be used to reduce the volume of the cystic hygroma to prevent facial deformities and airway obstruction. Close observation of the baby by a neonatalogist after birth is recommended. If resolution of the cystic hygroma does not occur before birth, a pediatric surgeon should be consulted.
Cystic hygromas that develop in the third trimester (after thirty weeks gestation) or in the postnatal period are usually not associated with chromosome abnormalities. There is a chance of recurrence after surgical removal of the cystic hygroma. The chance of recurrence depends on the extent of the cystic hygroma and whether the wall of the cyst was able to be completely removed.
Treatment involves removing all of the abnormal tissue. However, cystic hygromas can often spread to other parts of the neck, making it impossible to remove all of the tissue.
Other treatments have been tried with only limited success. These include:
- Chemotherapy medications
- Injection of sclerosing medications
- Radiation therapy
The outlook is good if surgery can totally remove the abnormal tissue. In cases where complete removal is not possible, the cystic hygroma commonly returns.
The outcome may also depend on what other chromosomal abnormalities or birth defects, if any, are present. The outcome is generally better for a baby that does not have a chromosome abnormality. About 60% of cystic hygromas result from chromosome abnormalities. The baby may have a set of abnormalities known as “genetic syndrome”.
Genetic syndromes with cystic hygroma as a clinical feature:
• The majority of prenatally diagnosed cystic hygromas are associated with Turner syndrome, a chromosome abnormality in which a female has only one X chromosome instead of two.
• Chromosome abnormalities such as trisomies 13, 18, and 21
• Noonan syndrome
- Damage to structures in the neck caused by surgery
- Return of the cystic hygroma
Calling your health care provider
If you notice a lump in your neck or your child’s neck, call your doctor.