The upper neck pouch sign: a prenatal sonographic marker for esophageal atresia.

Prenatal suspicion of esophageal atresia is usually based on the finding of a small or absent fetal stomach in association with polyhydramnios. As similar findings may be generated by other abnormalities, confirmation of the diagnosis is generally not possible until birth. We present a case in which the suspicion of esophageal atresia was raised in the 22nd week of pregnancy in the presence of a small stomach bubble associated with a persistent left superior vena cava. The diagnosis was confirmed 4 weeks later by direct visualization of the fluid-filled blind-ending esophagus during fetal swallowing, which we called the upper neck pouch sign. This is the first case in which the onset of this sonographic entity was specifically observed on serially repeated sonograms as early as the 22nd week. The appearance of this direct sign of esophageal atresia is described, and the literature is reviewed.