This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
A cystic hygroma is a fluid-filled sac that results from a blockage in the lymphatic system. It is most commonly located in the neck or head area, but can be located anywhere in the body. It may be discovered in a fetus during a pregnancy ultrasound, or it may be apparent at birth as a soft bulge under the skin. When it is identified on pregnancy ultrasound, there is an increased risk for miscarriage. In some cases, it is not discovered until a person is older. Symptoms can vary depending on its size and specific location, and it can potentially cause problems with nearby structures or organs.
A cystic hygroma may be caused by genetic or environmental factors that cause abnormal development of the lymphatic vascular system during embryonic growth. It may occur on its own or as part of a genetic syndrome with other features, such as Turner syndrome, Down syndrome or Noonan syndrome. In adults it may result from trauma, or from earlier respiratory infections. In many cases, the cause is not known.
Treatment involves removing the cystic hygroma, although removing all of it may not be possible. Other treatments that have been tried with limited success include chemotherapy, injection of sclerosing medicines, radiation therapy, and steroids.
For more information, visit GARD.