Body stalk anomaly in monozygotic twinning: a case report.

We describe a case of concordant body stalk anomaly in a monozygotic twin. Autopsy of the fetus showed abnormalities compatible with the maldevelopment of embryonic folding. Abdominal viscera were in a sac covered by the amnion and were attached directly to the placenta. The anus was not visible and no discernible external genitalia were noted. Other findings included a neural tube defect and a rectal duplication as an enteric cyst. Umbilical cord had only one vein and an artery. No abnormalities were found on pathologic examination of the placenta. Although we encountered cases previously with gastroschsis and omphalocele, this was the first case of body stalk anomaly that we recognized as an enteric cyst, which is extremely rare in twins.