孕妇,19岁。孕6+个月作常规超声检查,B超所见:胎儿双顶径6.2cm,左侧侧脑室扩张积液,最大前后径1.2cm(图1),纵切扫查胎儿脊柱时发现其骶尾部两排串珠样强回声中断,并在此处见一囊性包块突起,约5.5cm×4.8cm,边界清,壁薄,内部为无回声,可见条状光带。包块在羊水中漂动(图2),胎儿? Pregnant woman, 19 years old. Pregnancy 6+ months for routine ultrasound examination, B seen: fetal biparietal diameter 6.2cm, left lateral ventricle expansion fluid, the largest anteroposterior diameter 1.2cm (Figure 1), longitudinal scanning of the fetal spine found sacral Tail two beaded like strong echo interrupted, and here see a cystic mass protrusion, about 5.5cm × 4.8cm, clear boundary, thin wall, the internal echo-free, visible strip light. Mass in the amniotic fluid floating (Figure 2), fetus?