Fact-sheet: Colloid cyst
Updated on 03/26/2020 at 8:46 AM
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Definition
Benign lesions with mucoid content derived from endoderm.
Location: >99% are located on the midline, between the anterior columns of the fornix, facing the foramina of Monro, at the anterosuperior aspect of the third ventricle.
Centimetric size, stable over time.
Peak incidence around age 40, affecting men and women equally.
Clinical features
Often asymptomatic.
Recurrent headaches in 50% of cases.
Intracranial hypertension.
More rarely, memory disturbances, dementia, loss of consciousness.
CT
- Spherical or oval lesion, spontaneously hyperdense in 2/3 of cases, isodense in 1/3 of cases.
- No enhancement after contrast administration.
- Correlation between density and degree of hydration (useful preoperatively).
- Mono- or biventricular hydrocephalus.
MRI
- Usually hyperintense on T1 and isointense
on T2: hyperintense relative to parenchyma, sometimes with fine peripheral vascularity.
Hypointensity correlates with viscosity.
- FLAIR: no suppression.
- Diffusion: no restriction.
- Gadolinium: no enhancement.
- Flow MRI: to better assess the impact of the cyst on the foramina and delineate its contours.
Management
Risk: acute hydrocephalus.
Microsurgical treatment: complete resection by ventriculoscopy with cyst aspiration; histopathologic examination.
Differential diagnosis
Nearly pathognomonic location, but a few differential diagnoses:
- Craniopharyngioma
- Subependymoma
- Choroid plexus papilloma
- Xanthogranuloma
- Flow artifact on T2 FLAIR