Prenatal diagnosis of persistent left and absent right superior vena cava

We report a case of persistent left superior vena cava (LSVC) with absent right superior vena cava (RSVC) diagnosed prenatally. At 27 weeks' gestation, routine fetal ultrasonography showed an abnormal four-chamber view. Fetal echocardiography revealed a markedly enlarged coronary sinus in the four-chamber view. An absent RSVC and a persistent LSVC were demonstrated in the three-vessel view. No additional cardiac malformations were seen before birth. Postnatal imaging confirmed the prenatal diagnosis. The combination of persistent LSVC and absent RSVC without any other cardiac malformations is an extremely rare cardiac anomaly and less commonly detected in utero. Identification of a dilated coronary sinus in the four-chamber view, with atypical features in the three-vessel view, may lead to the antenatal diagnosis of this condition.