{"id":11204,"date":"2026-02-16T16:15:18","date_gmt":"2026-02-16T15:15:18","guid":{"rendered":"https:\/\/neurohirurgija.in.rs\/?page_id=11204"},"modified":"2026-06-17T08:06:33","modified_gmt":"2026-06-17T06:06:33","slug":"arachnoid-cyst","status":"publish","type":"page","link":"https:\/\/neurohirurgija.in.rs\/en\/arachnoid-cyst\/","title":{"rendered":"Arachnoid Cyst \u2014 Definition, Symptoms, Epilepsy Risk, and Treatment Options"},"content":{"rendered":"\n
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\n Author:<\/span>\n \n Dr. Zeljko Kojadinovic, MD, PhD\n <\/a>\n \u2014 Consultant Neurosurgeon\n <\/div>\n\n
\n Specialized Experience:<\/span>\n 30 years of clinical expertise in neurosurgery.\n <\/div>\n\n
\n Last medically reviewed:<\/span>\n June 16, 2026\n <\/div>\n<\/div>\n\n\n\n
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Who This Arachnoid Cyst Page Is For<\/h3>\n <\/div>\n\n

\n This page is intended for patients who have been diagnosed with an arachnoid cyst on MRI or CT scan, as well as for family members seeking a clear, structured explanation of what the finding truly means.\n <\/p>\n\n

\n Many people discover an arachnoid cyst incidentally while being evaluated for headaches, seizures, dizziness, or unrelated problems. You are not expected to read this page from start to finish. Instead, you may return to specific sections when new questions arise \u2014 for example, if follow-up imaging shows growth, symptoms change, or surgery is suggested.\n <\/p>\n\n

\n If medical opinions differ, surgery has been proposed without clear explanation, seizures are difficult to interpret, or you are unsure whether the cyst is truly responsible for symptoms, an individualized\n \n neurosurgical second opinion\n <\/a>\n can help clarify whether monitoring or intervention is the most appropriate next step.\n <\/p>\n<\/div>\n\n\n\n

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\n When patients seek a second opinion for an arachnoid cyst\n <\/div>\n\n
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\n \u2022 Surgery has been recommended, but it is unclear whether it is truly necessary\n <\/div>\n
\n \u2022 Different doctors provide conflicting advice (monitoring vs. operation)\n <\/div>\n
\n \u2022 Seizures are present and it is uncertain whether the cyst is the real cause\n <\/div>\n
\n \u2022 Follow-up MRI suggests cyst growth or increasing mass effect\n <\/div>\n
\n \u2022 Hydrocephalus, midline shift, or neurological symptoms are mentioned without clear explanation\n <\/div>\n
\n \u2022 There is uncertainty about the safest surgical option (endoscopic fenestration, open surgery, or cystoperitoneal shunt)\n <\/div>\n <\/div>\n\n
\n In most cases, arachnoid cysts do not require surgery \u2014 but in selected situations, careful evaluation is essential.\n If your situation involves uncertainty about indication, timing, or surgical strategy, you may request an individualized neurosurgical review here:\n \n Request Second Opinion\n <\/a>\n <\/div>\n\n<\/div>\n\n\n\n
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\n Arachnoid Cyst \u2014 Quick Summary (Read This First)\n <\/h3>\n\n
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  • An arachnoid cyst is a benign, fluid-filled cavity within the arachnoid brain membrane.<\/strong> It is not a tumor and does not become malignant.<\/li>\n\n
  • Most arachnoid cysts are congenital.<\/strong> They form during fetal development due to splitting of the arachnoid membrane which covers the brain. They are often discovered incidentally later in life.<\/li>\n\n
  • Arachnoid cysts are relatively common.<\/strong> They are found in approximately 1\u20132% of the population, and the majority remain asymptomatic throughout life.<\/li>\n\n
  • Only a minority (estimated 5\u201320%) become symptomatic, depending on cyst size and location.<\/strong> Most remain asymptomatic throughout life. Symptoms usually occur because of brain compression, progressive enlargement, or disturbance of cerebrospinal fluid (CSF) circulation.<\/li>\n\n\n
  • \n Not every symptom in a patient with a cyst is caused by the cyst.<\/strong> \n Careful clinical and radiological correlation is essential before considering surgery, particularly when the only findings are headache or epilepsy without clear evidence of mass effect, hydrocephalus, or progressive neurological deficit.\n<\/li>\n\n\n
  • MRI is the key diagnostic tool.<\/strong> A typical arachnoid cyst follows the CSF (normal brain fluid) signal on all sequences, shows no contrast enhancement, and contains no solid components.<\/li>\n\n
  • Surgery is not automatically required.<\/strong> Indications include progressive neurological deficits, documented growth, hydrocephalus, significant mass effect, or drug-resistant epilepsy clearly linked to the cyst.<\/li>\n\n
  • \n Surgical treatment depends primarily on cyst location and individual anatomy.<\/strong> \n Endoscopic fenestration<\/strong> is often preferred when the cyst can be safely connected to normal cerebrospinal fluid (CSF) spaces, such as the ventricular system or adjacent cisterns, allowing a minimally invasive internal opening. \n However, cysts with thick walls, multiloculated compartments, convexity or deep interhemispheric locations, or those lacking a safe adjacent CSF space for communication may require open microsurgical fenestration (craniotomy)<\/strong> to achieve a wider and more controlled opening. \n Cystoperitoneal shunting<\/strong> is generally reserved for selected cases in which fenestration is not technically feasible, has failed, or when long-term CSF diversion is necessary, particularly in the presence of persistent symptoms or associated hydrocephalus.\n<\/li>\n\n
  • \n Surgery aims to relieve symptoms rather than remove the cyst completely.<\/strong> \n In properly selected patients, clinical improvement occurs in most cases (approximately 70\u201385%), especially when symptoms are clearly caused by mass effect or hydrocephalus. \n The cyst often remains visible on follow-up imaging and may not significantly decrease in size.\n<\/li>\n\n\n
  • Long-term prognosis is generally favorable.<\/strong> Most patients live normal lives without intervention, and malignant transformation does not occur.<\/li>\n\n
  • This page is structured so you can focus on what applies to your situation.<\/strong> Use the Contents box to jump directly to sections on symptoms, epilepsy, treatment decisions, or follow-up.<\/li>\n\n <\/ul>\n<\/div>\n\n

    \n Most readers benefit from the Quick Summary plus the sections on Does the Cyst Need Treatment?<\/strong>, When Is Surgery Necessary?<\/strong>, and Relationship Between Arachnoid Cyst and Epilepsy<\/strong>. The remaining sections provide deeper clinical detail.\n<\/p>\n\n\n\n