Cystic hygroma in fetus

**Definition:** Development abnormalities of the lymphoid system that occur at sites of lymphatic-venous connection, most commonly in the posterior neck but may be anterior and may extend into chest. Frequently associated with karyotypic abnormalities, various malformation syndromes, and several teratogenic agents. When diagnosed prenatally, the overall prognosis is poor. Cystic hygroma diagnosed after birth is usually associated with a good prognosis.