کیست‌های آراکنویید کیسه‌های پر از مایع مغزی نخاعی هستند که بین مغز یا نخاع و غشای آراکنویید که یکی از سه غشایی است که مغز و نخاع را در بر می‌گیرد، واقع شده‌اند. کیست‌های آراکنوئیدی شایع‌ترین نوع کیست‌های مغز هستند. این کیست‌ها اغلب مادرزادی هستند و یا از بدو تولد (کیست‌های آراکنویید اولیه) وجود دارند. ضربه مغزی یا آسیب دیدگی نیز می‌تواند منجر به ایجاد کیست ثانویه آراکنویید شود. اکثریت کیست‌های آراکنوئید خارج از لوب گیجگاهی مغز در ناحیه‌ای از جمجمه که به عنوان حفره میانی جمجمه شناخته می‌شود، شکل می‌گیرند. کیست‌های آراکنویید که نخاع را درگیر می‌کنند، نادر هستند.

محل و اندازه این کیست شایع نمی باشد . بیمار با شکایت ضعف پیشرونده دست و پای راست مراجعه نموده بود که با استفاده از میکروسکوپ تحت عمل تخلیه کیست قرار گرفت . پس از عمل علائم بیمار بهبود یافت و در پیگیری یکساله عود کیست نداشته است

مردان 4 برابر بیشتر از زنان احتمال ابتلا به کیست آراکنوئید را دارند.

اکثر افراد مبتلا به کیست‌های آراکنویید علائم را قبل از سن 20 سالگی و به ویژه در اولین سال زندگی خود تجربه می‌کنند، اما برخی از افراد مبتلا به کیست‌های آراکنویید هرگز علائمی را نشان نمی‌دهند. مردان 4 برابر بیشتر از زنان احتمال ابتلا به کیست آراکنوئید را دارند.

علت

علت دقیق به وجود آمدن کیست‌های آراکنویید ناشناخته است. کیست‌های اولیه آراکنویید که مادرزادی هستند (در هنگام تولد وجود دارند) به علت اختلالات رشد مغز و نخاع در طول دوره ابتدایی جنینی هستند. کیست آراکنوئید ثانویه که به ندرت اتفاق می افتند، به دلیل ضربه مغزی، خونریزی مغزی، مننژیت، تومورهای مغزی و یا عوارض جراحی مغز شکل می‌گیرند. در بعضی موارد، کیست‌های آراکنویید بخشی از یک سندرم ژنتیکی نظیر سندرم چودلی مک کالو، موکو پلی ساکاریدوز یا سندرم مارفان هستند که علائم و نشانه‌های مربوط به سندرم خاص نیز همراه کیست وجود دارد.

اغلب موارد تشخیصی کیست‌های آراکنویید اسپورادیک(تک گیر) هستند و در افراد بدون سابقه خانوادگی ابتلا به کیست‌های آراکنوئید رخ می‌دهد. However, familial cases of arachnoid cysts have been reported in medicine, suggesting that genetics may play a role in the occurrence of these types of cysts in some individuals. For example, arachnoid cysts have been reported in at least three unrelated sets of siblings. In familial cases, the type of inheritance may be autosomal recessive.

Arachnoid cyst symptoms

In some cases, arachnoid cysts do not show any symptoms. The location and size of the cyst in each individual determines the occurrence of symptoms as well as when they may begin. The signs and symptoms of arachnoid cysts vary depending on where they are located around the brain and may include the following:

• Headache
• Nausea
• Vomiting
• Excessive accumulation of cerebrospinal fluid in the brain (hydrocephalus) and as a result increased intracranial pressure
• Deformation of some skull bones causing macrocephaly. , which is an abnormally large head (only in rare cases).
• Seizures
• Hearing and vision disturbances
• Dizziness
• Problems with balance and walking
• Neurological signs such as developmental delay, behavioral changes, inability to control voluntary movements (ataxia), problems with balance and walking, cognitive impairment, and weakness or paralysis on one side of the body (hemi parsi)
• Arachnoid cysts that surround the spinal cord can compress the spinal cord or nerve roots and may cause symptoms such as progressive back pain and leg pain or burning or numbness in the legs or arms and weakness. In some cases, other problems such as urinary or stool incontinence may occur.

Diagnosis

Diagnosis of arachnoid cysts is often done incidentally and often during the examination of a person having a seizure. Diagnosis may be based on a thorough patient history, a thorough clinical examination, and a variety of specialized tests, especially advanced imaging studies such as computed tomography (CT) and magnetic resonance imaging (MRI). CT scan and MRI can detect or confirm arachnoid cysts. CT scans and X-rays are used to create a film that shows cross-sectional images of the structure of brain tissue. During an MRI, a magnetic field and radio waves are used to create cross-sectional images of the brain.

Treatment

Most arachnoid cysts are found incidentally and remain stable in size. Many doctors recommend conservative treatment. In the absence of symptoms, treatment may not be necessary and affected individuals may be monitored periodically. If symptoms appear, the cyst can be re-evaluated. When treatment is necessary, specific treatment depends on the presence of symptoms, the size of the cyst, and the specific location of the cyst within the skull. In cases where treatment is recommended, treatment usually involves one of two methods: open craniotomy fenestration or ventriculoperitoneal shunt.

During fenestration craniotomy, a part of the skull is removed for the surgeon to access the cyst, where several holes are made in the wall of the cyst (fenestration), to drain the cerebrospinal fluid into the subarachnoid space, where the fluid returns to the surrounding tissue. It is absorbed and discharged. In addition, in some cases, the disease may be treated by placing a device (shunt) in the cyst to drain the cyst into the ventricular system of the brain or into the abdominal cavity. This surgery drains the cyst and creates a suitable passageway for the flow of cerebrospinal fluid.

Shunt

Shunting an arachnoid cyst is another treatment option. The surgeon inserts a tube into the cyst, which remains in place and drains the fluid. This liquid is absorbed in other parts of the body. However, the patient may depend on the shunt to prevent symptoms from returning, and living with a shunt can cause complications such as blockage or infection. Recently, advances in minimally invasive brain and skull surgery have transformed these routine procedures into fully endoscopic techniques, with shorter times, fewer complications, excellent results with faster recovery, and reduced patient mortality. While the approach varies depending on the size and location of the arachnoid cyst, endoscopic surgical management allows the surgeon better access for craniotomy fenestration or, in other cases, cyst removal without the complications and risks associated with brain manipulation or retraction. During treatment, a small number of clinics can offer facilities for minimally invasive fenestration, endoscopic shunting, endoscopic shunting, and complete endoscopic or assisted removal of arachnoid cysts.

Cyst removal

If possible, spinal arachnoid cysts can be treated with complete surgical resection. did Surgery generally results in the disappearance of symptoms. In some cases, complete removal of spinal cysts is not possible with surgery. In such cases, fenestration or shunting of the cyst to drain the fluid may be necessary. Other treatment is symptomatic and supportive.

Prognosis

Untreated arachnoid cysts may cause severe nerve damage when the cyst(s) expand or bleed into the cyst, damaging the brain or spinal cord. Symptoms usually improve or disappear with treatment.