Large congenital lymphatic venous malformation in a twin pregnancy: A case report

Congenital lymphatic venous malformations (LVMs) are rare, slow-flow vascular anomalies with highly variable presentations. While most pose no considerable risk to the pregnant individual or fetus, larger complex lesions, particularly in monochorionic-diamniotic twin pregnancies, are uncommon and present unique diagnostic and management challenges. A 27-year-old gravida 4, para 2 pregnant individual presented at 23 0/7 weeks’ gestation with a monochorionic-diamniotic twin pregnancy. Ultrasound and fetal magnetic resonance imaging (MRI) revealed a large T2 hyperintense cystic mass extending from the chest wall into the neck, axilla, and arm of twin B, consistent with a LVM. Multidisciplinary evaluation guided prenatal surveillance. At 31 2/7 weeks’ gestation, evolving hydrops and severe maternal pre-eclampsia necessitated cesarean delivery. Twin B required intubation for airway compression and remained hemodynamically stable. MRI confirmed a complex and extensive LVM with an extensive venous component. After multidisciplinary discussion, she was treated with rapamycin and later underwent limited resection, drainage and vacuum assisted closure of the left neck lesion, leading to resolution of the lesion with subsequent extubation by day of life (DOL) 43. She subsequently underwent limited aspiration, drainage, and vacuum assisted closure of the left chest wall. She demonstrated clinical improvement with early initiation of supportive therapies. Large fetal lymphovascular malformations require close monitoring and imaging surveillance throughout gestation due to the risk of potential lesion progression and hydrops fetalis.