Long-Segment Superior Vena Cava Hypoplasia as an Uncommon Cause of Non-immune Hydrops Fetalis.

Non-immune hydrops fetalis (NIHF) is a complex perinatal diagnosis with diverse and often idiopathic causes, including impaired lymphatic drainage and compromised venous return. We present the case of a newborn with large bilateral pleural effusions who was subsequently found to have a hypoplastic superior vena cava (SVC). Initially treated with thoracentesis and dietary changes, the infant's symptoms persisted. Follow-up imaging confirmed ongoing SVC narrowing, which was successfully treated with a stent. This case underscores the importance of identifying non-traditional causes of NIHF.