Colloid cysts are benign, cystic structures lined by an epithelial layer. Colloid cysts are characterized by the mucoid fluid content within the cyst.
Epidemiology
Colloid cysts account for approximately 0.5-1 % of all intracranial tumors. The typical age at initial diagnosis is 20-50 years[^3].
Location
Colloid cysts typically occur in the third ventricle, where they often obstruct CSF outflow and can therefore lead to hydrocephalus.
Symptoms
Colloid cysts are frequently asymptomatic incidental findings. However, when CSF circulation is impaired, colloid cysts can cause headaches, which are typically intermittent and severe and usually occur frontally[^1]. Nausea and vomiting are also frequently associated with the headache symptoms. CSF obstruction caused by a colloid cyst can also lead to altered consciousness and even death[^1].
Imaging
Colloid cysts can be visualized on CT or MRI imaging, where the cyst is usually located in the anterior portion of the third ventricle. On both MRI and CT imaging, colloid cysts show variable appearances but typically present as follows[^2]:
MRI imaging
MRI T1 sequence | MRI T2 sequence | MRI T1 with contrast |
Hyperintense | Hypointense | Minimal enhancement, in some cases limited to the capsule |
CT imaging
Calcifications are only rarely observed in colloid cysts[^2].
Noncontrast CT | Contrast-enhanced CT |
Hyperdense | Approximately 50 % show mild enhancement |
Treatment
Surgical resection of colloid cysts can be performed using microsurgical or endoscopic techniques[^4].
Prognosis
Incomplete resection of a colloid cyst carries a significant risk of cyst recurrence. [^5].
Histopathology
Surgical videos
Endoscopic transventricular resection of a colloid cyst
Operative video of the endoscopic removal of a colloid cyst.