Vitelline Vein Varix Diagnosed Postnatally Following a Prenatal Diagnosis of Umbilical Vein Varix: A Case Report and Review of the Literature

Vitelline vein varices are rare vascular abnormalities. Differentiating them from umbilical vein varices during the prenatal period is often challenging; however, thrombus formation can occur in the early postnatal period, potentially leading to portal vein thrombosis, extrahepatic portal vein obstruction, and portal hypertension. Therefore, early diagnosis and appropriate therapeutic intervention are crucial for these patients. We present a case that was initially diagnosed in utero as an umbilical vein varix but was subsequently confirmed after birth to be a vitelline vein varix complicated by portal vein thrombosis, which necessitated surgical intervention. The patient was a 35-year-old woman (gravida 2, para 1). At 26 weeks of gestation, a 15 mm cystic lesion with blood flow was identified within the fetal abdominal cavity and was initially thought to represent an umbilical vein varix. The patient was referred to our hospital at 29 weeks of gestation. During follow-up, the lesion increased in size to approximately 20 mm, and there was no evidence of thrombus formation. Fetal growth was appropriate for gestational age. The patient was admitted at 31 weeks of gestation. Due to her history of a previous cesarean delivery, an elective cesarean section was performed at 36 weeks, resulting in the delivery of a 2,744 g female infant with favorable Apgar scores. On postnatal day 11, abdominal ultrasonography revealed a thrombus extending from the main portal vein into the intrahepatic branches. Contrast-enhanced CT on day 21 demonstrated a varix communicating with the superior mesenteric vein, which led to the definitive diagnosis of a vitelline vein varix. Subsequently, anticoagulation therapy with heparin sodium was initiated on postnatal day 25, followed by resection of the varix and thrombectomy on postnatal day 26. The postoperative course was uneventful. This report underscores the importance of considering vitelline vein varices in the differential diagnosis of fetal intra-abdominal cystic lesions with blood flow. It also emphasizes the need for thorough prenatal evaluation and a multidisciplinary approach to perinatal management.