Colloid cyst | |
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Histopathology of colloid cyst | |
Classification and external resources | |
eMedicine | med/2906 radio/96 |
A colloid cyst is a cyst containing gelatinous material in the brain. It is almost always found just posterior to the foramen of Monro in the anterior aspect of the third ventricle, originating from the roof of the ventricle. Because of its location, it can cause obstructive hydrocephalus and increased intracranial pressure. Colloid cysts represent 0.5%-1% of intracranial tumors.
Symptoms can include headache, vertigo, memory deficits, diplopia, behavioral disturbances and in extreme cases, sudden death. Intermittency of symptoms is characteristic of this lesion. Untreated pressure caused by these cysts can result in brain herniation. Colloid cyst symptoms have been associated with 4 variables: cyst size, cyst imaging characteristics, ventricular size, and patient age. The developmental origin is unclear, though they may be of endodermal origin, which would explain the mucin-producing, ciliated cell type. These cysts can be surgically resected, and opinion is divided about the advisability of this.
Colloid cysts can be diagnosed by symptoms presented. Additional testing will be required and the colloid cyst symptoms can resemble those of other diseases. MRI and CT scans are often used to confirm diagnosis.
Patients with third ventricular colloid cysts become symptomatic when the tumor enlarges rapidly, causing CSF obstruction, ventriculomegaly, and increased intracranial pressure. Some cysts enlarge more gradually, however, allowing the patient to accommodate the enlarging mass without disruption of CSF flow, and the patient remains asymptomatic. In these cases, if the cyst stops growing, the patient can maintain a steady state between CSF production and absorption and may not require neurosurgical intervention. Various management options exist depending on the severity of symptoms and their effect on the patient. The main management options are: observation, craniotomy for microsurgical resection, neuroendoscopic removal, stereotactic drainage, and cerebrospinal fluid diversion with bilateral ventriculoperitoneal shunting placement.