Sirenomelia with esophageal atresia.

Sirenomelia, is a rare fatal condition characterized by fusion of the lower extremities. It has been suggested that sirenomelia is a severe form of caudal regression syndrome complex for which the pathogenesis is controversial. Our case is a sirenomelia associated with esophageal atresia and tracheoesophageal fistula. In the literature, it has been pointed out that the VATER association may represent a less severe form of sirenomelia but no sirenomelia case associated with esophageal atresia and tracheoesophageal fistula has been found. Finally, we detected a single large artery which diverts the blood of the embryo's caudal part to the placenta with the detailed autopsy especially with focusing on the abdominal vasculature. This vascular steal is thought to be the main pathogenic mechanism of the condition.