case_images: PMC9846037_01
case_images: Ultrasound images revealing the monochorionic twins and twin A's nuchal cystic hygromas and twin B's normal NT. (A) Two yolk sacs within a single gestational sac at 6+2 weeks. The arrow indicates two yolk sacs. (B) The monochorionic diamnitic twins with a separating membrane of T sign at 10+3 weeks. The arrow indicates the distinct T sign of the separating membrane between the twins. (C) Nuchal cystic hygromas of twin A at 12+3 weeks. The arrows indicate the nuchal cystic hygromas of twin A from longitudinal section and transverse section. (D) The normal NT of twin B at 12+3 weeks. NT, nuchal translucency.
case_images: fmed-09-1055275-g001.jpg
case_images: PMC9846037_01_fmed-09-1055275-g001.jpg
case_images: F1
case_images: Her first ultrasonography at 6+2 weeks of gestation documented two yolk sacs within a single gestational sac (Figure 1A). The subsequent scan at 10+3 weeks of gestation demonstrated MC diamniotic twins with a T-shaped insertion of the membrane (Figure 1B). Unfortunately, one of the twins (twin A) was revealed to have nuchal cystic hygroma and generalized hydrops without abnormal volume of amniotic fluid on ultrasonography at the time of routine nuchal transparency (NT) screening (Figure 1C). At the same time, no abnormalities were found on the other fetus (twin B) by detailed ultrasonic examination (Figure 1D).