Ultrasound Features and Management of Body Stalk Anomaly

This study describes the prenatal diagnosis of body stalk anomaly (BSA) in a large series of affected pregnancies and proposes an algorithm for the differential diagnosis of abdominal wall defects in the first trimester.

This was a retrospective study of all the cases of BSA diagnosed in our tertiary unit between 2009 and 2015. In all cases, we performed a detailed ultrasound examination with particular emphasis on the appearance of the amniotic membrane and content of the amniotic sac and the coelomic cavity.

The study included 17 cases of BSA (15 singleton pregnancies, one dichorionic-diamniotic twin pregnancy discordant for BSA and one case of conjoined twins) at a median gestational age of 12+3 (range 11+0 to 16+6) weeks. In all cases, the liver and bowel were herniated into the coelomic cavity and the amniotic sac was intact containing the rest of the fetus with a normal amount of amniotic fluid; additionally, there was severe kyphoscoliosis and positional abnormalities of the lower limbs. The umbilical cord was absent, but umbilical vessels were seen with color Doppler running from the placenta to the fetus marginally to the eviscerated abdominal content.

BSA can be easily diagnosed from 11 weeks' gestation. Examination of the amniotic membrane continuity, content of both the amniotic sac and coelomic cavity and a short umbilical cord help in differentiating this condition from other abdominal wall defects.