Double-outlet single ventricle and an abdominal vascular mass: in utero diagnosis with pathological confirmation.

A fetal echocardiographic scan was performed when routine prenatal ultrasound screening failed to identify four cardiac chambers. The scan showed a single ventricle with an associated circoid varicosity. Because of these anomalies, amniocentesis was suggested and trisomy 18 confirmed. The presence of major cardiac structural anomaly should prompt careful and specific review of all fetal anatomy to screen for syndrome identification and consideration of amniocentesis.