Cystic Hygromas

Most of this information came from the Emory University's School of Medicine Department of Human Genetics.

A cystic hygroma is a fluid-filled sac that results 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. Some cystic hygromas are present at birth and called congenital cystic hygromas. Others can develop over the course of a person's life. Some cases of congenital 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.

Cystic hygromas occur in approximately one percent of fetuses during the ninth through the 16th week of pregnancy.

A cystic hygroma can occur on its own or with chromosomal abnormalities such as Turner Syndrome, Trisomy 18 and 13 and Down's Syndrome. It is more common with Turner's Syndrome, though.

Some cystic hygromas will resolve on their own, but not always. A cystic hygroma can be present in a healthy baby. If no chromosome abnormality is found and the problem has resolved itself by 18 to 20 weeks, the outcome is good in 54 to 80 percent. The percentage drops if it hasn't resolved. Hydrops, which is life-threatening swelling of a fetus, occurs in 22 to 76 percent of the time with a cystic hygroma and is almost always associated with miscarriage or fetal death.