The progression of mediastinal lymphangioma in utero

We describe a case of mediastinal lymphangioma that suddenly progressed inu tero. The initial sonographic impression was one of pericardial effusion wh ile the follow-up examination revealed a mediastinal cystic mass. At 35 wee ks of gestation preterm labor occurred. An ultrasound examination performed at this time demonstrated the mediastinal cyst with internal hemorrhage an d fetal hydrops. The cystic mass was resected 5 days after birth. The diagn osis of lymphangioma was made from histological examination. The infant was followed up for 18 months and remained well. We recommend frequent prenata l sonographic follow-up intrathoracic cystic hygroma had suddenly increased in size when a localized fluid collection is shown in the inducing hydrops fetalis. The internal echoes presumably mediastinum.