Choroid plexus cyst MRI

Axial Flair shows nodular masses in bilateral atria of lateral ventricles, non enhancing on post contrast T1 with typical restricted diffusion on Dw images suggestive of Choroid Plexus Cysts. 

Syn: Choroid plexus xanthogranuloma.
A non neoplastic, non inflammatory cysts of choroid plexus lined by compressed connective tissue found at both ends of age spectrum.
o Adult: CPC is common incidental finding on imaging studies in older patients (approximately
40% prevalence)
o Fetus: CPCs seen in 1% of second trimester pregnancies.

Best diagnostic clue on imaging:
o Older patient with nodular cystic or nodular partially cystic masses on MRI with restricted diffusion.
o Fetus or newborn with large (> 2 mm) choroid plexus cysts on Antenatal Usg.
Location : Atria of lateral ventricles most common site. Usually bilateral.
Size: Variable, Usually 2-8 mm. Rarely large > 2 cm.

On CT
NECT
o Iso- or slightly hyperdense compared to CSF
o Irregular, peripheral Ca++ in majority of adult cases
CECT: Varies from none to rim or solid enhancement.

On MRI
• T1WI: Iso/slightly hyperintense compared to CSF
• T2WI: Hyperintense compared to CSF
• PD/lntermediate: Hyperintense
• FLAIR: 2/3rd iso-, 1/3rd hypointense on FLAIR
• T2* GRE: Blooms with intracystic hemorrhage (rare)
• DWI: 65% show restricted diffusion (high signal)
• Tl C+
o Enhancement varies from none to strong
o Variable pattern (solid, ring, nodular)
o Delayed scans may show filling in of contrast within cysts.

Differential Diagnosis
Ependymal cyst
• Doesn't enhance
• Usually unilateral
• Attenuation, signal more like CSF
Neoplasm
• Choroid plexus papilloma (children < 10 y; strong relatively uniform enhancement; cystic variant reported but rare)
• Meningioma (usually solid)
• Metastasis (rarely cystic)
• Cystic astrocytoma (rare in older patients)

Pathogenesis
Lipid from desquamating, degenerating choroid epithelium accumulates in choroid plexus - Lipid provokes xanthomatous response and result in Choroid plexus cysts formation.

Clinical presentation
Mostly asymptomatic, discovered incidentally at imaging
Rarely headache.
Age, prevalence increases with age.
No gender preponderance.

Reference : Diagnostic imaging Osborn.