How are bilateral choroid plexus cysts formed in the fetus?

Patient's question:

19 weeks onset time

Doctor's answer:

Analysis of the condition: Hello, fetal choroid plexus cysts can disappear after 26 weeks of gestation. If they disappear, it is a normal phenomenon and there is no need to worry. If they persist, it may be caused by chromosomal abnormalities.
Recommendations: It is recommended to regularly monitor the situation. If the cysts do not continue to grow and remain smaller than 1 cm, there is no need to worry. They should disappear by 26 weeks.