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Arachnoid gyst

button print blu20 Arachnoid Cyst

(Code CIE-9-MC: 348.0)

Arachnoid it costs, also known as leptomeningeal cysts.

Arachnoid cysts (QA) are benign pathological structures of features that could be defined as cavities filled with clear fluid similar to cerebrospinal fluid (CSF) contained within a membrane of the arachnoid histologically indistinguishable healthy.

Occur during the division of the arachnoid.

The most accepted hypothesis of impaired speech separation endomenix in the third quarter of the neonatal period. The membrane is endomenix mesenchymal tissue surrounding the tube. In the third quarter, when it goes through the roof of the fourth ventricle, CSF pressure waves flowing through it, the dissected into two layers and give rise to the pia mater, the arachnoid and subarachnoid space. Alterations of this mechanism may lead to the formation of separate cavities, in their growth, form cysts.

Others speak of hypotheses that are secondary to focal brain hypoplasia, which occupy the space provided or produced by alterations in the secretion of substances from the subarachnoid space to the venous system. Also, to further explain the cyst growth theories have emerged, among them the most widely accepted, because there are cases where it has been demonstrated in vivo, is the formation of valve mechanisms. Have also been described in the literature sometimes cysts meningeal infections and related trauma, called side, in contrast to those for which the cause is unknown and congenital malformation is suspected, and designated as primary.

Actually they are cysts intraaracnoideos. When diagnosed at middle fossa were called "syndrome" lobe agenesis. (This term is now obsolete).

Others are caused by trauma.

A simple linear fracture without immediate complications, may lead to the development of an arachnoid cyst, hence the need to maintain a proper monitoring of the evolution of fracture healing and etiological alert to the appearance of neurological symptoms.


They are a typical diagnosis of childhood, especially in the first two years of life, which represent approximately 1% of intracranial expanding lesions. The most common locations are found in various series the Sylvian fissure and posterior fossa.

5 for 1000 in autopsias.son lesions characteristic of childhood, slightly more common in males.

Also found at the spinal level but are rare.


  • Sylvian fissure 49%
  • APC 11%
  • Supracolicular 10%
  • Vermian 9%
  • Sellar and suprasellar 9%
  • Interhemispheric 5%
  • Convexity 4%
  • Clivus 3%

Histological Types

Simple cysts: cell line appear to be capable of CSF secretion. The middle fossa cysts appear to be exclusively of this type

Cysts can also contain complex glia, ependyma, and other tissue types.

quistearacnoideoanatpat2 Arachnoid Cyst

quistearacnoideoanatpat1 Arachnoid Cyst

Clinical presentation

The symptoms are variable depending on which part of the central nervous system compresses, the most striking are focal symptoms with signs of increased intracranial pressure such as headache (headache), hemiparesis, diplopia (double vision), irritability, mood swings, apathy (lack of emotions), and impaired mental performance.

Middle fossa with suprasellar supra or infratentorial diffuse hydrocephalus hydrocephalus

Epilepsy, headache, hemiparesis HTE, Craneomegalia, delayed development, visual loss, precocious puberty HTE, craneomegalia, late development

Most cysts are symptomatic in infancy.

Can be diagnosed by the presence of:

  • Symptoms of increased intracranial pressure (headache, nausea ...)
  • Epilepsy.
  • Sudden deterioration: due to hemorrhage (in cyst or ): medial fossa cysts are prone to bleeding due to the increased possibility of bridging veins rupture, due to rupture of the cyst
  • Protrusion in the skull
  • Focal neurological signs.
  • Incidental finding.
  • Hydrocephalus (probably due to compression of the third ventricle)
  • Yes, endocrine symptoms: occur by 60%. Includes precocious puberty.

    visual Impairment

  • In posterior fossa usually produce nonspecific symptoms such as hearing loss and tinnitus sometimes even difficult to distinguish from
  • Meniere's disease and most often characteristic cerebellar ataxias.


Are diagnosed primarily by TAC.

The ideal method MRI and diffusion sequences (better raise the differential diagnosis with neoplastic epidermoid cysts or hemangioblastomas).

Differential Diagnosis

  • Sticos chemical astrocytomas.
  • Cisterna magna large
  • Cyst hidatí-dico - Cysticercosis
  • Myocardial old crebral
  • Porencephaly.
  • Cavum of midline.


It is recommended to treat only the symptoms occur regardless of location and size. Treatment is still controversial.

Treatment options have endoscopic fenestration or craniotomy into the ventricle or subarachnoid space and the implantation of a shunt.

Probably the best treatment consists in the derivation of the cyst to the peritoneum.

Method Advantages Disadvantages

Aspiration-Quick and easy drill Recurrence

Craniotomy with excision of the fenestration to wall quísticay subarachnoid or ventricular cyst Allows inspection and vascular structures. Avoid Some houses in permanent shunt. Reaccumulation possible and more invasive.

Simple Procedure Unit peritoneal shunt Shunt and Shunt carry risks.

Dr. J. Sales Llopis

Department of Neurosurgery, General University Hospital of Alicante.

Comments (156) Trackbacks (1)
  1. Hello I have my grandfather 81 ala years time that he made a MRI the result of the interpretation is as follows :
    multiple pulse sequences were performed T1, T2 , FLAIR , Diffusion , AND , getting multiplanar images which shows :
    ocupativas symmetrical brain parenchyma lesions not identified, with decrease in brain volume widely , grooves comprominencia .
    draws attention aranoideo the presence of cyst in the left parietal region , with measures 20x18x21 mm.
    the nuclei of the base with adequate volume and intensity as well as morphology concervados .
    the optic chiasm , pituitary gland and pituitary stalk with volume and signal intensisad consercados .
    corpus callosum present without alteriaciones in their morphology
    the supratentorial ventricular system with bulging breaks , increased volume of compensatory and sisternas way to the base with increased volume .
    mesencefalo , pons and medulla unchanged .
    craniocervical junction is concervada and normal caraccteristicas.
    cerebellar hemispheres and vermis size , form , situation and normal signal intensity .
    the fourth ventricle is Central and adequate volume .
    no restriction areas are observed to superspreading .
    after the administration of intravenous contrast material , no zones are observed normal refuerso .
    estruccturas unaltered orbits .
    estruccturas of the internal auditory canals are symmetric and normal signal intensity .
    the tissue is normal .
    decrease in brain volume in relation to cortico subcortical atrophy
    arachnoid cyst in the left parietal region.
    suggested correlation with clinical studies.

  2. hello my name gladly Jose and I am from Honduras good I just want to know or ask him if he knows or is aware of any al-natural medicine, as there is a patient who was operated three times to the head and had an arachnoid cyst and operations will be obstructed occipital nerve, and many suffer from constant headaches and that leads him to take a lot of medication, ay sele placed a valve and the valve is not work contact me agrarecere much blessings:

  3. Hello, I have a child 5 years old,in February 2011, slipped and hit his head was, what he did to take him to the doctor, they did a CAT scan and was diagnosed with the following:

    The computerized tomographic brain injury is done by continuous axial slices 5 m.m.s. thick, I agree to planar obtained in digital panoramic radiography, without the use of iodized substance and supplemented contrast to bone algorithm, Mostar:

    The normality of the supratentorial parenchymal structures with appropriate differentiation of gray and white matter in the brain stem and posterior fossa while large central cyst homogeneous seen the occipital bone remodeling, bilateral extension of the fourth ventricle and centrally communicates, the latter increased volumen. The cerebellar hemispheres are reduced toward the midline.

    Supratentorial ventricular system topography, dimensions and normal morphology with long occipital horns and IV ventricle volume increased.
    A cisternal level emphasizes the preservation of cerebral and cerebellar cortical furrows and the basal cisterns and peritroncales.

    Centromedial structures without deviations in relation to the midline.
    No extra axial collections intracranial.
    Bony structures of cranial vault base and post-traumatic disorders.

    Normal brain. Large posterior fossa cyst communicating with the fourth ventricle.
    Absence of parenchymal lesions and extra-axial post-traumatic intracranial.

    We took him to some of the best specialists in the country and they have all said the same, which is very common, that their behavior is normal, and let all, any reaction except.
    Not to operate, and you should do your normal life.

    Although the cyst is about 5cm to date has not complained about any of the issues listed in the previous reviews as vomiting, head pain severe, etc..

    About a year ago we realized that when I tried to look closely, one eye is deviated and took him to the doctor and was diagnosed,"Accommodative esotropia with ac / a high", and the doctor says it has nothing to do with the cyst.

    My questions are:
    1.- How to know if a cyst or a mega cisterna.
    2.- It has something to do with accommodative esotropia with ac / a high.
    3.- I have to give a test to see if the cyst could have grown or complications.
    4.- I have to have some special care at school, or when playing?

    I am a father of Lima, Peru, worried about my only son and I get very sad all this topic.
    Thank you.

    • my daughter is having the same and also will detour one eye started to wear glasses always tell you that it has nothing to do with it but it is no coincidence that three people I know the same thing happens only faith in God and do not let the operating mine it detected a year and already has four and thank GOD is living a normal life

    • Hello, I have 33 years old, multiple cysts aracnoideos, and included a intramural. Until today, thank God, I have made my life normally, to the point that almost no cysts think. I understand your concern because I am also mother, but the only recommendation I can give, is to calm down and try to influence him that calm your child, for trouble us no benefit in these cases. Teach your child to live life fully and responsibility. Much encouragement and strength. A hug

  4. Male, 40 years old. Suffer headaches since last May, y tomo Lyrica 25 (morning and night) y Sirdalud (night). I was diagnosed with a cyst will aracnoideo (see the transcript of the two tests). I am waiting for an appointment with the neurosurgeon. What is your opinion?. I am particularly concerned about a possible operation. Do you think it will be necessary?.

    Thank you very much.

    TC skull SIN contrast
    F. realization: 13/06/2012.
    Headache three weeks in male 40 AP years without interest, especially when trying to concentrate or exercise. The pain is located left parietal level. Ruega rule organicidad (commented with neurology).
    CT skull without IV contrast administration.
    A hypodense large image occupies the most anterior portion of the left temporal fossa is identified, adapting to the rest of the time the lesion parenchyma without obvious mass effect condition. On the characteristics and location probably corresponds to said image arachnoid cyst without evidence of complications associated. However, existence of symptoms rating given complete MRI study.
    Rest of brain parenchyma without evidence of relevant findings.
    Likely left temporal arachnoid cyst without obvious complications.

    MRI brain SIN / contrast
    F. realization: 29/06/2012.
    Tensional headache. Nonspecific mareo.
    RM skull without IV contrast administration.
    Image is identified in the most anterior portion of the left temporal fossa described in previous TC. This lesion has signal intensity similar to CSF ​​on all sequences. The temporal adjacent parenchyma adapts to the presence of the lesion, changing its outline but without evident mass effect or perilesional edema or other changes in the adjacent parenchyma. Nor associated hemorrhagic component or alterations in the next bone structures. No restriction on diffusion sequence. All findings described corresponds to arachnoid cyst without evidence of associated complications.
    Rest of brain parenchyma without evidence of relevant findings.
    Temporal arachnoid cyst left without complications associated.

  5. Goodnight Doctor, known to have a son 14 and a half years and when I was 1 year and eight months they went about 6 arachnoid at the height of the left brain trying Neuro cysts side you will Operate and I put a drain valve which almost completely cysts, but more happens that for the month of February this year I started to get a headache and constant vomiting earlier were each 15 days each week and then after almost spending a day, they began to treat chronic migraines that electroencephalogram was apparently nothing, but then a month ago I kept vomiting and take him to the hospital and gave him seizures and a MRI they did become aware of a cyst in the left front, apparently we were told boy put the valve on the left side was doing its job, but all this could be due to new cyst detected, for this we began to administer Keppra 250 milligrams, but a week like you turned the table begins with headache, right arm and then start throwing up every hour for a day or so with pseudoseizures until triggered a seizure in which he lost consciousness, for a few minutes and often returned well but back with problems in language and motor skills but recovered in a day, in this situation followed him up the medication because they said they needed to reach the exact dose being with keppra (levetiracetam) 500 milligrams in the morning and 500 milligrams in the evening and 1 hour after this medicine 1 capsule Epamin 100 milligrams (Phenytoin Sodium) morning and evening, but this last time was given on Thursday morning the table hard 1 day and a half of vomiting and headache, but Dr. Neurologist who is very professional treating you said giving him four crises were not seizures but could be anxiety attacks and we will carry out a videoencefalograma, to determine the activity at the time having the box, Doctor I'm worried is that after these pictures my son is struck even in the penultimate frame he rose to levetiracetam 750 mg on day, but began to have suicidal thoughts and you returned to the dose indicated above, but equally so went the psychiatrist and was prescribed these medications paroxetine 10 grams per 8 Olanzapine in the morning and a quarter tablet at 21H00 and when taking the pictures 6 drops of each clonazepan 12 hours 3 drops the 3 These days every twelve hours equal, it worries me that this is happening every 8 days and my son is with 38 low kilos and increasingly more weight by the constant vomiting and treating neurologist according to states that seizures would be neutralized by the amount of medication administered, but what worries me is the onset of symptoms with headaches and vomiting that are one and a half although no seizures triggered in, but if these bouts of depression that does not lose consciousness, but if it is gone with his confused eyes, Doctor ask me for some advice about it and God Bless You

  6. hello, my son 14 years was operated arachnoidal cyst left parietal “giant”, neurosurgeon used a system that involves making a avertura in the skull of no more than 7 millimeters in diameter for which introduces an instrument with which camera “breaks” this bag of fluid that it is responsible for eliminating horganismo naturally, not needing any element llamese “tube” to remove the fluid from the cyst, thank God it turned, the cyst is shrinking considerably and the brain is no longer making dough (is not compressed by the cyst”, Days neurosurgeon will Avaria Base Hospital Los Angeles, besides being a very good professional is a good person, very human and we are very grateful to him and his team.
    I would also add that my son did not nungún symptom, was a finding, my son when he put out a scanner showed this cyst and when we went to another neurosurgeon Concepcion said we had to put a tube from the cyst to the thorax, which thank God was not necessary for this new breakthrough in medicine, Greetings and trust in God at all times.


  8. my husband has 67 years was diagnosed a left left temporal arachnoid cyst and frontal subcortical ischemic focus when he made a resonance magnetic, I am very worried because in a period of 1 forgot what time to , Now this normal , however painful, arms

  9. I have 47 years and the scan says: “image observed 14 mm x 7 mm located in the deep sector left sylvian valley below and behind the basal ganglia which could correspond to arachnoid cyst” I wonder if this has to dispel any treatment or have to remove it with ciruía?? Thanks for your input.

  10. I was diagnosed with an arachnoid cyst of 6.3 cm diameter, is located in the anterior aspect of the left middle fossa and fissure silvio. Could enviarne information about this. M not sure if they operate q. But many dolored d m gives head and precione.

  11. I have my seven 7 years is restless they did an EEG result was mild bioelectric hase 5 days made him magnetic resonanci result arachnoid cyst 40 by 20 mm left brain celebrero are intact and I want to know which is concerned arachnoid cyst treatment for breast jumps

  12. hi my number is claudia. make 6 years my son had surgery for a left temporal cyst and make approximately 2 months suffered a seizure,repeat studies and resonance comes out again or small cyst. Great question and I certainly, may reappear if the doctor tell you volveira happen anymore and would love someone to help me answer what is the next step. quisa a new ciruguia??? thanks

  13. my son is 7 years has learning disability ,speaking he was made an electroencephalogram ,result bioelectric slight disorganization ,and also a resonance result is observed magnetic ensanchamientofocal the subarachnoid space of the left middle fossa arachnoid cyst support. reaches 40 by 20 mm maximum diameter . focale no lesions are identified at the level of brain parenchyma ,ni cerebellar brain stem , basal cisterns,sylvian subarachnoid spaces and convexity of conserved gauge. ventricular morphology system ,respected position and size. midline centered. My son is medicated with valproic acid syrup logical āveśe has strong headache. treatment that is done to the cyst await your response and I am very concerned since you owe the response of jumping'm a mom worried


  15. Hi I have 31 years when I was the age of 8 years found me a large arachnoid cyst on the right side of my head (Poarte of the back) in all my life I spent a clear normal life if in pain (mentioned) in low season for example hours and disappears after vulve to me in months or years far today 7 June 2012 I already wear 3 days with more or less severe pain and will not let me sleep besides wanting to sleep and this dizzy,to pass? will be growing?? se abra roto?

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