AbstractDespite the rapid advances in fetal medicine and pediatric surgery, congenital chylothoraces have an associated mortality of 22–65% and an increased morbidity resulting from pulmonary hypoplasia, severe infections secondary to immune globulin deficiencies, protein malnutrition, and coagulopathy. While the mainstay of therapy is medical management, large volume chylothoraces often require surgical management. In both the prenatal and postnatal periods, the recommended management of congenital chylothoraces is still controversial. We present a case of a prenatally diagnosed large chylothorax associated with a cervical lymphatic malformation. In our patient, the chylothorax persisted despite optimal postnatal medical management with dr...