What are the other Names for this Condition? (Also known as/Synonyms)

• CNS Epidermoid Cyst
• Epidermoid Cyst of the Central Nervous System
• Intracranial Epidermoid Cyst

What is Epidermoid Cyst of Brain? (Definition/Background Information)

• Epidermoid Cyst of Brain is an uncommon benign cyst observed anywhere in the brain, but usually seen at the cerebellopontine angle (CPA). This cystic tumor is mostly diagnosed in young adults, and is also known as an Intracranial Epidermoid Cyst
• An epidermoid cyst is a common skin cyst that is generally observed in middle-aged adults. It occurs on the skin as a painless nodule. This benign cyst can be present anywhere in the body, but is most commonly found in the head and neck region
• The cause and risk factors for Epidermoid Cyst of Brain are unknown. It is believed to develop during pregnancy, in the fetal stage. Some reports indicate that the cyst may also develop due to certain iatrogenic or external factors
• Small-sized Epidermoid Brain Cysts may not present any significant signs and symptoms. However, large tumors may cause headaches, nausea and vomiting, vision impairment, and memory issues, depending on the location of the tumor
• In some cases, the treatment of Epidermoid Cyst of Brain may involve surgery that is considered curative. In most cases, the prognosis is excellent with appropriate early treatment, since it is a benign cystic lesion. However, an incomplete removal may result in recurrence of the cyst

Who gets Epidermoid Cyst of Brain? (Age and Sex Distribution)

• Epidermoid Cyst of Brain is a rare cystic tumor typically observed to have a congenital origin. However, symptom manifestation is more common in the 20 to 40 years’ age group (i.e., among young individuals)
• Both males and females are affected, and a slight male preference is observed
• Individuals of all racial and ethnic background may be affected

What are the Risk Factors for Epidermoid Cyst of Brain? (Predisposing Factors)

• Currently, no risk factors have been identified for Epidermoid Cyst of Brain

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Epidermoid Cyst of Brain? (Etiology)

The cause of development of Epidermoid Cyst of Brain is unknown. Researchers have proposed the following mechanisms to explain cyst formation.

• The epidermoid cyst is typically a congenital lesion that develops during pregnancy (embryogenesis). The lesion reportedly forms when certain displaced epithelial cells are abnormally entrapped within the brain tissue, during early embryo development
• The epithelial cells may be abnormally placed (trapped) in the brain following an injury or surgical procedure. Thus, it is reported that the condition may be acquired too

The condition is not caused by what the expectant mother does or does not do, either prior to or during pregnancy.

What are the Signs and Symptoms of Epidermoid Cyst of Brain?

The signs and symptoms of Epidermoid Cysts of Brain can vary from one individual to another and depends on the size and location of the cystic tumor. In general, most cysts are small, and no significant symptoms are observed; although, large tumors are known to present symptoms. In many individuals, tumors that grow slowly and remain asymptomatic, may be diagnosed during certain radiological imaging studies of the head and neck or spinal cord region, which are performed for unrelated health conditions.

A vast majority of the Epidermoid Brain Cysts are found within the brain tissue (called intradural tumors), with the most common site being the cerebellopontine angle (CPA). Between 40-50% of the cysts are diagnosed at this location. The other lesser affected sites include the fourth ventricle (in 17% of the cases), the suprasellar cistern (region above the pituitary gland, in 10-15% of the cases), and the middle cranial fossa (about 5% of the cases). Occasionally, tumors are known to involve the brainstem, pineal gland, and the temporal lobes. 10% of the tumors are located extradurally i.e., within the skull, but outside the dura mater. These fluid-filled lesions may also be observed anywhere along the neuraxis (along the entire spinal cord); although, spinal cord tumors are extremely rare.

Most Epidermoid Cysts of Brain are asymptomatic. In some, the signs and symptoms observed may include:

• Persistent headaches
• Nausea and vomiting; giddiness
• Visual impairment, such as eyelid abnormality, visual field defects, rapid eye movements, and poor eyesight
• Impaired movement, including walking difficulties
• Hearing impairment
• In general, any cranial nerve can be involved by the cysts causing a variety of symptoms, such as impaired vision, loss of taste, hearing loss, loss of touch sensation, twitching of facial muscles, difficulty in eating and chewing, etc.
• Numbness and tingling sensation
• Muscle weakness; loss of strength in the arms of legs
• Neck pain
• Speech problems
• Insomnia or loss of sleep, or excessive sleepiness (usually during daytime)
• Tremors
• Seizures or convulsions
• Lack of coordination; unsteadiness and loss of balance (vertigo)
• Dizziness and fainting
• Increased intracranial pressure may be observed if there is obstruction of the cerebrospinal fluid (CSF) drainage, since the ventricular system may be affected. This may result in nausea, vomiting, headaches, and seizures
• Memory loss
• Confusion
• Mental impairment
• Changes in one’s behavior; personality changes

Large cysts can cause significant signs and symptoms. Most of the cases represent single cysts; but occasionally, multiple cysts can be detected.

How is Epidermoid Cyst of Brain Diagnosed?

A majority of cystic brain tumors may remain undiagnosed for prolonged periods, if they are asymptomatic and generally slow-growing. The slow development of symptoms may contribute to a delayed detection and diagnosis of these cysts. They may be detected when there is a sudden worsening of symptoms prompting the healthcare provider to perform radiological studies of the brain and/or spinal cord.

The diagnosis of Epidermoid Cyst of Brain may involve the following tests and examinations:

• Complete physical examination and a thorough medical history
• Assessment of the presenting signs and symptoms
• Neurological, motor skills, and cognitive assessment:
  • Checking intellectual ability, memory, mental health and function, language skills, judgment and reasoning, coordination and balance, reflexes, and sensory perceptions (space, sight, hearing, touch, etc.)
  • The healthcare provider/neurologist may use the Karnofsky Performance Scale in order to assess the neurological functioning of the individual’s central nervous system (CNS)
• Electroencephalography (EEG)
• Electromyography with nerve conductivity tests
• Imaging studies that may be performed include:
  • X-ray of head and neck and/or vertebral column
  • Computerized tomography (CT) scan of the head and neck region and/or vertebral column; CT with contrast
  • Magnetic resonance imaging (MRI) scan of the central nervous system (brain and spine); MRI with contrast agents such as gadolinium
  • Cerebral angiographic studies or MR angiography: An angiogram involves injecting dye into the bloodstream, which makes the blood vessels to appear visually on X-rays. The X-ray may show a tumor in the brain or the blood vessels leading into the tumor
  • Magnetic resonance spectroscopy: This radiological technique is used to study the chemical profile of the tumor. It is often performed with and compared to corresponding MRI scan images of the affected region
  • Positron emission tomography (PET scan): A PET scan is a nuclear medicine imaging technique that uses three-dimensional images to show how tissue and organs are functioning. It may be performed to detect any malignancy, and if there is a metastasis (spread) of the tumor to other regions
• Cerebrospinal fluid analysis, where a spinal tap or lumbar puncture procedure may be performed: This diagnostic test is used to remove a sample of cerebrospinal fluid (CSF) from the spaces in and around the brain and spinal cord. The sample is removed from the lower spinal cord using a thin needle, and it is then checked for the presence of cancer cells
• Molecular studies, if necessary

Tissue biopsy: A biopsy of the affected region (brain or spinal cord) is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy sample under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy sample under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis.

A differential diagnosis to eliminate other conditions or tumor types may be considered, before arriving at a definitive diagnosis.

The radiological differential diagnosis may include:

• Acoustic schwannoma
• Arachnoid cyst
• Craniopharyngioma
• Cystic tumors
• Dermoid cyst
• Inflammatory cysts
• Mega cisterna magna
• Meningioma
• Neurocysticercosis

The pathological differential diagnosis may include:

• Adamantinomatous craniopharyngioma
• Dermoid cyst
• Endodermal cyst
• Papillary craniopharyngioma
• Rathke’s cleft cyst

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Epidermoid Cyst of Brain?

The complications of Epidermoid Cyst of Brain may include the following:

• Stress and anxiety due to fear of a brain tumor
• Large cystic tumor masses may get secondarily infected with bacteria or fungus
• Tumor rupture may cause a form of meningitis, called aseptic meningitis
• Occasionally, recurrence of the tumor following its incomplete surgical removal; the recurrence may take months to years
• Such recurrent tumors may transform to malignancies over a long period of time; the most common malignancy arising from such a tumor is squamous cell carcinoma
• Damage to the muscles, vital nerves, and blood vessels, during surgery
• Post-surgical infection at the wound site is a potential complication

How is Epidermoid Cyst of Brain Treated?

The treatment of Epidermoid Cyst of Brain may involve the following:

• In some cases of small tumors and considering their slow-growing rates, the healthcare provider may propose conservative ‘wait and watch’ measures, instead of immediately recommending surgery to remove them
• Generally, the treatment of choice is a complete surgical excision for all such cystic tumors. The surgeon may use certain microsurgical approaches to remove the cyst
• Additionally, chemotherapy and/or radiation therapy may be necessary for malignant tumors
• Follow-up care with regular screening and check-ups are important and encouraged

How can Epidermoid Cyst of Brain be Prevented?

Currently, there are no known methods available to prevent the occurrence of Epidermoid Cyst of Brain.

What is the Prognosis of Epidermoid Cyst of Brain? (Outcomes/Resolutions)

• The prognosis for Epidermoid Cyst of Brain is excellent with appropriate treatment, since it is a benign cyst
• In case of a malignant transformation of the recurrent tumor, the prognosis depends on several factors including on the tumor stage

Additional and Relevant Useful Information for Epidermoid Cyst of Brain:

The following article link will help you understand other cancers and benign tumors:

http://www.dovemed.com/diseases-conditions/cancer/