Colloid Cyst

Introduction

The brain is a highly complex organ, not only in terms of the diversity and importance of the critical functions that it performs but also in terms of its structure. The functional tissues of the organ are known as its parenchyma. Brain parenchyma is not arranged as a uniform mass. In fact, it is interspersed with a series of interlinked ventricles or cavities that together form what is known as the ventricular system of the brain. The cerebrospinal fluid that protects the brain from injury and also performs the role of waste clearance, flows through the ventricular system. These passages also connect with the central canal of the spinal cord.

One problem that could potentially arise in the ventricular system is that of hydrocephalus. It occurs when the flow of cerebrospinal fluid is, for any of a number of reasons, blocked or impaired. One of the probable causes of hydrocephalus is a condition known as a colloid cyst.

What Is A Colloid Cyst?

Cysts are abnormal masses consisting of fluid enclosed within a membranous sac. Rarely, some cysts contain semi-solid or gelatinous substances as well. An example of this is a certain type known as a colloid cyst. This is a rare condition. Colloid cysts are generally associated with the third ventricle of the brain. To be specific they are usually situated on the roof of the third ventricle. Less often, they have also been identified in the frontal lobe and cerebellum.

These cysts are considered to be benign in nature but colloid cysts can nevertheless give rise to serious complications such as hydrocephalus. If this state of affairs is allowed to worsen, patients may be left with lifelong brain damage or they may even die.

What Causes Such Cysts To Form?

The true cause for the formation of colloid cysts remains unknown at present. Most often these lesions are diagnosed in middle-aged individuals. However, instances of such lesions in the brains of children are not unknown of. In fact, it is speculated that the condition could be a congenital one but that it might only be diagnosed much later on in life if it produces symptoms.

It is not clear whether the condition is connected to hereditary genetic mutations although in some instances familial patterns of occurrences have indeed been observed.  

What Are Some Symptoms Of Colloid Cysts?

Colloid cysts are not always symptomatic. When they are, the symptoms are rather vague and only diagnostic imaging can reveal the nature of the problem responsible for them. Symptoms tend to come and go, to increase and decrease in severity.

Patients may complain of:

• Headaches. These can be sudden and severe. The headache tends to intensify when leaning the head forward.
• Nausea.
• Vomiting.
• Confusion.
• Short-term memory loss.
• Abnormal gait.
• Urinary incontinence.
• Loss of consciousness.  

What Are Some Probable Complications?

If you have a colloid cyst in the brain, you could potentially develop a range of severe complications. Usually, this happens when the cyst grows very large. Some potential complications are discussed below:

• Temporary paralysis: Sometimes patients may develop a temporary form of paralysis, usually in the legs. This can have severe consequences because the patient could gravely injure themselves when paralysis sets in.
• Hydrocephalus: Patients develop hydrocephalus when something interferes with the normal mechanism that maintains a balance between the production, absorption, and circulation of cerebrospinal fluid in the brain and spinal cord. In this case, a particularly large colloid cyst could impair the normal circulation of CSF and give rise to hydrocephalus. This can produce a range of neurological symptoms including vision problems, memory deficits, and even seizures.
• Ventriculomegaly: An extra large colloidal cyst can cause the ventricles to become abnormally dilated.
• Increased intracranial pressure: The abnormal accumulation of fluid in the ventricles (hydrocephalus), if not addressed in time, can give rise to a buildup of pressure within the skull. As a result, the patient will display symptoms related to the neurological disturbance. This is a life-threatening condition and should be treated as a medical emergency.
• Brain herniation: When the pressure within the skull is extremely high, this forces the brain tissues out of their normal position. The brain may even squeeze through any available gap such as space at the bottom of the skull through which the spinal cord emerges. This can leave the patient with permanent brain damage.

How Is This Condition Diagnosed And Treated?

The neurological symptoms being displayed by patients will alert the doctor to a potential problem involving the central nervous system. The best way to investigate this and arrive at a definitive diagnosis without invasive methods is diagnostic imaging. The following procedures may be involved:

• Physical examination.
• Medical history.
• Ultrasound.
• Computerized tomography (CT).
• Magnetic resonance imaging (MRI).

Some of the methods to treat colloidal cyst are as follows:

• Endoscopic surgery– an endoscope (along with some surgical tools) is guided to the third ventricle of the brain by means of a hole drilled into the skull. This is a less invasive surgery which removes the complete cyst.
• Craniotomy-this is more invasive surgery as compared to the endoscopic surgery as it involves exposing the cyst by opening the skull. The removal of the cyst is comparatively easier as the cyst can be directly seen in this case.
• The stereotactic aspiration-this procedure involves the draining of the cyst by means of a needle. This helps in reducing the pressure inside the brain (during hydrocephalus) as the size of the cyst reduces.

In cases where the lining of the cyst or the cyst wall is not removed along with the contents of this cyst, the risk of recurrence is high. Prior to the surgery, the healing of the brain is essential in order to prevent any trauma to the brain which might lead to the recurrence of the cyst.

Colloid cysts are usually congenital and cannot be prevented.

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