Cystic hygromas are fluid-filled sacs that result from a blockage in the lymphatic system. The lymphatic system is a network of vessels that maintains fluids in the blood, as well as transports fats and immune system cells. Cystic hygromas are single or multiple cysts found mostly in the neck region. A cystic hygroma can be present as a birth defect (congenital) or develop at any time during a person’s life. Some cases of cystic hygromas resolve leading to webbed neck, edema (swelling), and a lymphangioma (a benign yellowish-tan tumor on the skin composed of swollen lymph vessels). In other instances the hygroma can progress in size to become larger than the fetus.
Causes of Cystic hygromas may result from environmental factors, genetic factors, or unknown factors.
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
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.