These ultrasound images show a cystic lesion in the placenta,located just below the placental surface. Few mobile echoes were seen within the lesion. No other abnormalities were seen in the placenta and the fetus. This finding is generally considered to be insignificant clinically. However some reports suggest an association with fetal IUGR (Intrauterine growth retardation).
It may be called:
subchorionic cyst of the placenta Or membranous cyst Or chorionic cyst.
It is believed to be due to deposition of fibrin in the subchorionic region of the placenta.