Choroid plexus cyst, also known as CPC, refers to a small fluid-filled sac that forms in the choroid plexus of the brain during fetal development. This term has a few synonyms that are used interchangeably with it, such as fetal intracranial cyst, brain cyst, or cerebral cyst. The choroid plexus is an area in the brain that produces cerebrospinal fluid, which helps cushion and protect the brain and spinal cord. Though choroid plexus cysts are generally harmless and usually disappear on their own by the end of pregnancy, in some cases they can be indicative of other abnormalities or chromosomal disorders. In any case, regular and careful monitoring is recommended to ensure the health of the developing fetus.