A cystic hygroma is a mass that commonly occurs in the head and neck area. It is a birth defect.
Causes, incidence, and risk factors
A cystic hygroma occurs as the baby grows in the womb. It forms from pieces of material that carry fluid and white blood cells. Such material is called embryonic lymphatic tissue. After birth, a cystic hygroma usually looks like a soft bulge under the skin. The cyst may not be recognized at birth. It typically grows as the child does, and sometimes is not noticed until the child is older.
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.