Quiste arachnoid

(Código CIE-9-CM: 348.0)

arachnoid, also known as cysts leptomení & shy; ngeos.

Arachnoid cysts (QA) are pathological structures Featu & shy; benign sticas that Scatter symbol & shy; masters defined as filled cavities li & shy; I clear liquid similar to li & shy; & shy cerebral spinal liquid; deo (LCR), contained within a membrane indistinguishable histologically healthy arachnoid.

Occur during the division of the arachnoid.

The most accepted hypothesis speaks of changes in the separation of endomenix in the third quarter of perí & shy; odo neonatal. The membrane is endomenix mesenchymal tissue surrounding the neural tube. In the third quarter, when the roof of the fourth breaks Ventri & shy; ass, CSF pressure waves flowing through it, the dissected into two layers and result pial, arachnoid and subarachnoid space. Alterations of this mechanism Scatter symbol & shy; an lead to the formation of separate cavities that, growth in, formarí & shy; an cysts.

Other hypotheses are saying that are secondary to focal brain hypoplasia, in which occupy the space provided or produced by alterations of the secretion of substances from the subarachnoid space to the venous system. Also, to explain the posterior cyst growth have raised several TEORI & shy; as; including, the most 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 in some cases related cysts meningeal and injuries, called secondary, as opposed to those for which the cause is unknown and suspected congenital malformation, and designated primary.

Really it is intraaracnoideos cysts. When diagnosed at the level of were called ” yes & shy; ndrome ” de de agenesis . (This term is now obsolete).

Others are caused by trauma.

An fracture Simple linear, without immediate complications, can cause the development of an arachnoid cyst, hence & shy; you must maintain proper monitoring of the evolution of consolidation fracture and an etiologic alert to the emergence of clini & shy; neurological nica.


They provide a diagnosis you & shy; peak childhood, especially in the first two years of life, which represent approximately 1% of intracranial expansive lesions. The most common locations found in various series are the Sylvian fissure and posterior fossa.

5 by 1000 in autopsias.son injuries Featu & shy; sticas childhood, slightly more common in males.

Also found at the spinal level, although they are rare.


  • Cisura de silvio 49%
  • APC 11%
  • Supracolicular 10%
  • Vermiano 9%
  • Sellar and suprasellar 9%
  • Interhemisférico 5%
  • Convexity 4%
  • Clivus 3%

Histological types

Simple cysts: Li & shy; cell line appear to be capable of secretion CSF. The cysts of the middle fossa speak exclusively of this type

Complex cysts that may also contain , epéndimo, and other types of tissue.

Quiste Aracnoideo

Quiste Aracnoideo

Presentation CLI & shy; nica

The sintomatologí & shy; varies according to the filesystem central compress, the most striking focal symptoms are signs of intracranial hypertension, as are headache (headache), hemiparesis,diplopia (double vision), irritability, mood swings, apatí­a (emotionless), and impaired intellectual performance.

Trench Media suprasellar with fuzzy supra or infratentorial hydrocephalus hydrocephalus

,headache,hemiparesia HTE,Craneomegalia,development Tardi & shy; or,loss of visual acuity,precocious puberty HTE,craneomegalia,development Tardi & shy; or

The Mayori & shy; to cysts are symptomatic in infancy.

Can be diagnosed by the presence of:

  • Yes & shy; symptoms of increased intracranial pressure (Headache, sickness…)
  • Epilepsy.
  • Sudden deterioration: due to bleeding (in cyst or subdural): pit medial cysts are prone to bleeding due to the increased possibility of rupture of bridging veins; due to rupture of the cyst
  • Protrusion in the skull
  • Focal neurological signs.
  • Incidental finding.
  • Hydrocephalus (Probably due to compression of the third Ventri & shy; ass)
  • Yes & shy; endocrine symptoms: occurring in a 60%. Includes precocious puberty.
  • Visual impairment
  • In posterior fossa usually produce other & shy; & shy nonspeci symptoms, such as hearing loss and tinnitus tists sometimes even difficult to distinguish from Meniere's disease and most Featu & shy; stico usually cerebellar ataxias.


Are diagnosed primarily by TAC.

The ideal method of diffusion MRI sequences (Maybe it will raise the differential diagnosis with epidermoid cysts or neoplastic hemangioblastomas).

Differential Diagnosis

  • Astrocitomas you & shy; STICOS.
  • Wemer cistern
  • Hidatí & shy cyst doctor – Cisticercosis
  • Myocardial old crebral
  • Porencefalia.
  • Hollow of Li & shy; NEA Media.


It is recommended to treat only those producing other & shy; symptoms regardless of the location and size. Treatment is still controversial.

Therapeutic 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 cyst peritoneum.

Method Advantages Disadvantages

Aspiration- drill and fast Recurrence

Craneotomí & shy; a with excision of the wall ere & shy; sticay fenestration to subarachnoid or ventricular space allows inspection of the cyst and vascular structures. Evita in some cases permanent shunt. Possible re-accumulation and more invasive.

Cystoperitoneal Simple Derivation Procedure Unit Shunt and risks of carrying Shunt.

Dr. J. Sales Llopis

Service Neurocirugí & shy; at the University General Hospital of Alicante.

To consult:

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157 Replies

  1. humberto says:

    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. taco says:

    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: anubis15chacal.an@yahoo.com

  3. Xavier says:

    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.

    • catalina says:

      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

    • VICTORIA says:

      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. chateante says:

    Male, 40 years old. Suffer headaches since last May, y tomo Lyrica 25 (morning and night) y Sirdalud (night). He has been diagnosed me arachnoid cyst (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 that image probably corresponds to arachnoid cyst without evidence of associated complications. However, existence of symptoms rating given complete MRI study.
    Rest of brain parenchyma without evidence of relevant findings.
    Likely arachnoid cyst left temporal without apparent 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.
    Quiste arachnoid left temporal no associated complications.

  5. Mark Delatorre says:

    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. sergio says:

    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. LUCY says:

    my husband has 67 years it detected a arachnoid cyst left temporal and left 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. Agnes says:

    I have 47 years and the scan says: “image observed 14 mm x 7 mm located in the deep valley left sylvian sector under 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. Roxana Rodriguez says:

    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 Magnetic days made him resonanci result is arachnoid cyst 40 by 20 mm left side of the brain and are intact celebrero I want to know what treatment arachnoid cyst worried mom jumps

  12. claudia says:

    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 Magnetic result is observed ensanchamientofocal the subarachnoid space left middle fossa support arachnoid cyst .reaches the 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. luis says:

    Hi I have 31 years when I was the age of 8 years found me a great 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?

  1. 10 February 2013

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