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Colloid Cyst


A Colloid Cyst is a collection of gelatinous material in the brain.


Colloid cysts arise within the brain. The cysts are well-encapsulated and consist of a layer of connective tissue covered with cells. The wall encapsulates a thick, gelatinous (colloid-like) material.

Symptomatic cysts vary from 6 mm to 9 cm in diameter, but usually range from 1 to 3 cm. They usually take origin from the roof of the third ventricle just posterior to the foramen of Monro within the brain (the third ventricle is the median cavity in the brain bounded by the thalamus and the hypothalamus on either side, and anteriorly by the optic chiasm).

A colloid cyst in the third ventricle of the brain can lead to hydrocephalus. Hydrocephalus is the increased accumulation of cerebrospinal fluid within the ventricles of the brain.


The cause of colloid cysts is unknown.


Symptoms usually occur in adults and may be dramatic, with episodes of headache, weakness of the limbs, and loss of consciousness. These symptoms are attributed to intermittent, acute episodes of hydrocephalus due to blockage of the foramen of Monro by the mobile cyst.


Your physician will take a complete medical history and perform a physical examination. Radiologic tests may include a head CT (computed tomography) scan or head MRI (magnetic resonance imaging).


In most cases, the recommended treatment is surgical removal of the cyst. The threat of death due to a benign tumor has led to the belief that symptomatic colloid cysts should be treated.


Where is the colloid cyst located in the brain?

What does it consist of?

Is it malignant or benign?

Will the symptoms get worse?

What will happen if the cyst is left intact?

What surgical techniques can be used to excise it?

What are the risks of surgery?