[Title Page - Prenatal Diagnosis of Large Intra- and Extra-Abdominal Umbilical Vein Aneurysm Complicated by Occluded Perforation with a Successful Outcome].

Introduction ▼ An aneurysm is a sac formed by localized dilatation of the wall of an artery, a vein, or the heart and the most common site is the abdominal aorta (Dorland’s Medical Dictionary, 32nd Edition, ­Elsevier,­ 2013)­ and­ is­ differentiated­ from­ an­ intra-abdominal­ ­umbilical­vein­varix­that­may­be­seen­as­a­cyst­-like­structure­in­ the­ fetal­ upper­ abdomen­ with­ venous­ flow­ on­ color­ Doppler­ ­interrogation.­The­term­umbilical­varix­is­defined­as­being­more­ than 9 mm or with a ratio of more than 50 % between the dilated and­a­more­distal­normal­ intra-abdominal­portion­of­ the­vein­ (Radiopedia.org, 2014). Fetal vascular ectasia on the other hand­is­defined­as­vascular­distension­to­at­least­four­times­the­ diameter of an adjacent muscular vessel of similar caliber (MM. Parast et al. Hum Pathol. 2008; 39: 948–953). Ectasia can expand to aneurysm size over time. True cysts of the umbilical cord originate from embryonic remnants, such as the allantois or omphalomesenteric duct, and their characteristic histological feature is the presence of an epithelial lining and they have a similar ultrasound appearance to pseudocysts. Therefore, prenatal differentiation­may­be­difficult.­In­general,­abnormalities­of­the­ fetal umbilical vessels are rare, and aneurysmal dilatation of the umbilical vein in particular is an uncommon vascular anomaly that can only be detected prenatally by detailed ultrasound examination of the umbilical cord (W. Sepulveda. Ultrasound Obstet Gynecol; 13: 157–60). This lesion is associated with increased fetal­morbidity­ and­mortality.­Owing­ to­ its­ three-dimensional­ structure, thorough inspection of the umbilical cord remains a challenging­task,­but­aneurysm­and­varix­of­umbilical­vessels­are­ potentially­life-threatening­to­the­fetus.­Nevertheless,­with­accurate prenatal diagnosis, antenatal intervention may be possible and fetal death averted with timely delivery (O. Shen et al. J­­Ultrasound­Med.­2007;­26:­251–253).­We­report­a­case­of­intra-­ and­extraabdominal aneurysmal dilatation of the umbilical vein Pränatale Diagnose und Management eines Feten mit großem, gedeckt perforiertem Aneurysma der Nabelvene mit intra-und extraabdominellen Anteil