Choroid Plexus Cyst
A choroid plexus cyst is a small fluid-filled sac that develops within the choroid plexus, the tissue inside the brain ventricles responsible for producing cerebrospinal fluid (CSF). These cysts are most commonly identified before birth during prenatal ultrasound, although they may also be seen in children and adults. Choroid plexus cysts are typically benign, usually do not affect brain function, and often resolve on their own. In most cases, they are considered a normal developmental variant rather than a disease.
What is it?
The choroid plexus is specialized tissue located inside the ventricles of the brain that produces cerebrospinal fluid. During fetal development, small pockets of fluid may become trapped within this tissue, forming choroid plexus cysts.
These cysts are not tumors and generally do not interfere with normal choroid plexus function. During pregnancy, they are most often identified during routine second-trimester ultrasound examinations and commonly resolve spontaneously before birth.
When a choroid plexus cyst is found in isolation without other abnormalities, it is usually considered a benign developmental variation that does not affect fetal brain development. In some pregnancies, additional imaging or genetic evaluation may be considered if other ultrasound findings are present, since multiple abnormalities together can sometimes be associated with chromosomal conditions.
In children and adults, choroid plexus cysts are usually incidental findings on MRI or CT imaging and are rarely associated with neurological symptoms.
MRI is the preferred imaging test after birth because it provides detailed visualization of the ventricles and surrounding brain structures. MRI can confirm that the lesion is fluid-filled and help distinguish it from other cystic or choroid plexus lesions. Prenatal ultrasound remains the standard method for detecting these cysts during pregnancy.
Important to Know
Most choroid plexus cysts are harmless and require no treatment. In prenatal cases, the cysts commonly resolve by the third trimester and usually do not affect development when isolated.
When cysts persist after birth or are discovered later in life, they are generally managed conservatively and rarely cause symptoms. In uncommon situations where a cyst becomes large enough to obstruct cerebrospinal fluid flow, additional evaluation and treatment may be considered.
Routine follow-up imaging is often unnecessary for typical isolated cysts unless symptoms or atypical imaging features are present.
Red flag symptoms in children or adults include sudden severe headache, repeated vomiting, vision changes, balance difficulties, seizures, or loss of consciousness. These symptoms require prompt medical evaluation and are more likely related to another neurological condition than to a typical choroid plexus cyst.