Central nervous system cyst

Symptoms are assessed on a case-by-case basis.[5] Some cysts in the CNS can be asymptomatic (producing or showing no symptoms), depending on their location in the brain or spinal cord. If the cysts develop in critical areas of the central nervous system, they can present one or more of the following symptoms:[6]

• Pressure in the spinal cord or brain  
• Rupture of nerves around the cyst
• Weakness in specific parts of the body controlled by the cyst-infected brain region
• Inflammation
• Hydrocephalus[7]
• Brainstem hemorrhage
• Seizures[5]
• Visual disturbances and hearing loss
• Headache[6]
• Difficulty with balance or walking[6]

In general, symptoms vary depending on the type of cyst and its location within the CNS.

Many CNS cysts form in the womb during the first few weeks of development as a result of congenital defects.[7]  In adults cysts may also form due to a head injury or trauma, resulting in necrotic tissues (dead tissue), and can sometimes be associated with cancerous tumors or infection in the brain. However, the underlying reasons for cyst formation are still unknown.[7]

CT scan of a colloid cyst

The diagnostic process typically begins with a medical history workup followed by a medical examination by a physician. Imaging tests, such as CT scans and MRIs, help provide a clearer picture. The physician typically looks for fluid (or other bodily substance) filled sacs to appear in the scans, as is shown in the CT scan of a colloid cyst. A primary health care provider will refer an individual to a neurologist or neurosurgeon for further examination. Other diagnostic methods include radiological examinations and macroscopic examinations. After a diagnosis has been made, immunohistochemistry may be used to differentiate between epithelial cysts and arachnoid cysts.[2] These examinations are useful to get a general idea of possible treatment options, but can be unsatisfactory to diagnose CNS cysts.[3][5] Professionals still do not fully understand how cysts form; however, analyzing the walls of different cyst types, using electron microscopes and light microscopes, has proven to be the best diagnostic tool. This has led to more accurate cyst classification and correct course of action for treatments that are cyst specific. In the past, before imaging scans or tests were available, medical professionals could only diagnose cysts via exploratory surgery.[2]

Treatment is often largely dependent on the type of cyst. Asymptomatic cysts, termed pseudocysts, normally require active monitoring with periodic scans for future growth.[7] Symptomatic (producing or showing symptoms) cysts may require surgical removal if they are present in areas where brain damage is unavoidable, or if they produce chronic symptoms disruptive to the quality of life of the patient. Some examples of cyst removal procedures include: permanent drainage, fenestration, and endoscopic cyst fenestration.[3]

Cysts derived from CNS tissues are very common in America.[2] They are a subtype of cerebrovascular diseases, which are the third leading cause of death in America.[2] Generally, CNS cysts are present in all geographic regions, races, ages, and sexes.[8] However, certain types of CNS cysts are more prevalent in certain types of individuals than others. Some examples of incidence rates in specific types of cysts include:[1]

• Arachnoid cysts are more prevalent in males than females
• Colloid cysts are more prevalent in adults
• Dermoid cysts are more prevalent in children under 10 years of age
• Epidermoid cysts are more prevalent in middle-aged adults