These are benign brain masses but may need urgent neurological and neurosurgical management if symptomatic
- Developmental cystic abnormality containing epithelial cells
- May be fluid-filled with a viscous fluid which is PAS-positive
- Incidence 3 per Million per year and 1% of all brain neoplasms
- Can cause acute intermittent or progressive hydrocephalus due to blocking CSF
- This can result in brain herniation
- Sudden death in children and young adults due to herniation or neurocardiac affects
- Sudden death is very rare
- Often asymptomatic picked up on neuroimaging
- May cause intermittent headaches which may be positional, intermittent and short-lasting
- Raised ICP Coma, Sudden death, Papilloedema
- Progressive dementia, hypomania
- Reports of causing seizures
- Lumbar puncture should be avoided if there is considered the risk of brain herniation
- CT:usually hyperdense and seen within the anterior aspect of the 3rd ventricle. Rarely seen in lateral or IVth ventricle. May be evidence of obstructive hydrocephalus with dilatation of the lateral ventricles and brain atrophy if chronic.
- MRI:T2 hyperintense or have a hypointense centre. They do not enhance.
- The risk of death in symptomatic patients was 3.1%. Several risk factors for symptomatic lesions were identified
- Age < 65 years
- Presence of headache on presentation
- Cyst diameter ≥ 7 mm on axial imaging
- Hyperintensity on FLAIR MRI
- Colloid cyst within a third ventricle risk zone.
- Neurosurgical review. Asymptomatic patients may have a wait and see approach with follow up scans to ensure no change radiologically and monitoring symptoms.
- Surgical treatment and resection where possible especially if symptoms or evidence of hydrocephalus. Some may offer endoscopic surgery.
- Ventriculoperitoneal shunt may be needed for hydrocephalus