Bilateral choroid plexus cysts are cysts found in the choroid plexus of both the right and left lateral ventricles of the fetus. Choroid plexus cysts are a developmental abnormality of the central nervous system during fetal life, which usually occurs in fetuses between 14 and 24 weeks of gestation, when small cysts of 3.0 mm or more in diameter are found in the lateral ventricular choroid plexus during ultrasonography. Most of these cysts disappear after the 26th week of pregnancy and do not significantly affect the development of the child, while some fetal choroid plexus cysts may show progressive enlargement and require further investigations, such as amniocentesis or cord blood aspiration, for chromosomal examination to rule out developmental abnormalities.