ABSTRACT
Lymphatic malformations (LMs) constitute one subset of a larger group of so-called vascular malformations, which may affect any segment of the vascular tree, including arterial, venous, capillary, and lymphatic vessels. Commonly referred to as "cystic hygroma" or "lymphangioma" in the historic literature, LMs consist of a group of developmental anomalies of the lymphatic system. Most LMs are sporadic, but some exhibit classic Mendelian inheritance. LMs are often diagnosed by prenatal ultrasound in the late first trimester. The differential diagnosis of a cystic lesion in the fetus is extensive, but in experienced hands, the correct diagnosis can be made in most cases. Occasionally, a fetus may be identified with a large anterior cervical LM that causes airway obstruction. Those LMs that are not diagnosed prenatally are generally evident at birth or before age 2 years; however, occasionally, they can manifest suddenly in older children and adults due to intralesional bleeding or infection.
