arachnoid_cysts tipo ppt.pdf
TRANSCRIPT
A h id C tA h id C tArachnoid CystsArachnoid CystsDean D. LinDean D. Lin
Department of NeurosurgeryDepartment of NeurosurgeryU i it f Fl idU i it f Fl idUniversity of FloridaUniversity of FloridaNovember 24, 2004November 24, 2004
OutlineOutlineOutlineOutline
EpidemiologyEpidemiologyPresentationPresentationLocationsLocationsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsPathologyPathologyTreatmentTreatment
DefinitionDefinitionDefinitionDefinition
“Benign, congenital, intra“Benign, congenital, intra--arachnoidal arachnoidal spacespace--occupying lesions filled with occupying lesions filled with
clear CSFclear CSF--like fluid”like fluid”
EpidemiologyEpidemiologyEpidemiologyEpidemiologyIncidence: 1% of intracranial mass lesionsIncidence: 1% of intracranial mass lesions
Age: 75% present during childhoodAge: 75% present during childhoodS i l 5S i l 5thth d d M Fd d M FSpinal: 5Spinal: 5thth decade, M=Fdecade, M=F
Gender: M:F = 3:1Gender: M:F = 3:1Gender: M:F 3:1Gender: M:F 3:1
Left side involved twice as frequentlyLeft side involved twice as frequentlyq yq y
Genetics: typically sporadic, nonGenetics: typically sporadic, non--syndromicsyndromic
EtiologyEtiologyEtiologyEtiology
Poorly UnderstoodPoorly UnderstoodPoorly UnderstoodPoorly Understood
“Old ” h th i “ litti ”“Old ” h th i “ litti ”“Older” hypothesis: “splitting” or “Older” hypothesis: “splitting” or diverticulum of developing arachnoiddiverticulum of developing arachnoid
“Newer” hypothesis: failure of frontal & “Newer” hypothesis: failure of frontal & ypyptemporal embryonic meninges to merge at temporal embryonic meninges to merge at sylvian fissuesylvian fissueyy
EtiologyEtiologyEtiologyEtiologyPotential mechanisms:Potential mechanisms:
Acti e secretion of CSFActi e secretion of CSF like fl idlike fl idActive secretion of CSFActive secretion of CSF--like fluid like fluid by cyst wallby cyst wall
Distention by CSF pulsationsDistention by CSF pulsations
Entrapment by oneEntrapment by one--way/ballway/ball--valve valve flowflow
Osmotic gradientOsmotic gradientOs ot c g ad e tOs ot c g ad e t
Spine: defect of Spine: defect of septum septum titiposticum posticum (thin membranous partition of (thin membranous partition of
the dorsal thoracic spinal cord)the dorsal thoracic spinal cord)
Associated AbnormalitiesAssociated AbnormalitiesAssociated AbnormalitiesAssociated Abnormalities
Temporal lobe hypoplasiaTemporal lobe hypoplasiaTemporal lobe hypoplasiaTemporal lobe hypoplasia
HematomaHematoma –– subdural and intrasubdural and intra--cysticcysticHematoma Hematoma subdural and intrasubdural and intra--cysticcysticTearing of bridging veinsTearing of bridging veinsAssociated with mild head injuryAssociated with mild head injuryj yj y
MacrocephalyMacrocephalyMacrocephalyMacrocephaly
Spinal arachnoid cysts: kyphoscoliosisSpinal arachnoid cysts: kyphoscoliosisSpinal arachnoid cysts: kyphoscoliosisSpinal arachnoid cysts: kyphoscoliosis
OutlineOutlineOutlineOutline
EpidemiologyEpidemiologyPresentationPresentationLocationsLocationsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsPathologyPathologyTreatmentTreatment
PresentationPresentationPresentationPresentationNatural history Natural history –– unclearunclearyy
Most cranial cysts do not enlargeMost cranial cysts do not enlargeSpinal cysts frequently enlargeSpinal cysts frequently enlarge
6060--80% symptomatic80% symptomatic
Most common symptoms:Most common symptoms:HeadacheHeadacheHeadacheHeadacheSeizureSeizureFocal deficitsFocal deficits
PresentationPresentationPresentationPresentationOther signs/symptoms:Other signs/symptoms:g y pg y p
Protrusion of skull, widen spinal canalProtrusion of skull, widen spinal canal
SuprasellarSuprasellarSuprasellarSuprasellarVisual impairmentVisual impairmentEndocrinopathies (up to 60% suprasellar cysts)Endocrinopathies (up to 60% suprasellar cysts)“Bobble“Bobble--head doll syndrome”head doll syndrome”
22--3/second AP bobbing3/second AP bobbing
Spine Spine –– pain/cord compressionpain/cord compressionIntermittent claudication, spasticityIntermittent claudication, spasticityWorse with ValsalvaWorse with ValsalvaWorse with ValsalvaWorse with Valsalva
OutlineOutlineOutlineOutline
EpidemiologyEpidemiologyPresentationPresentationLocationsLocationsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsPathologyPathologyTreatmentTreatment
LocationsLocationsLocationsLocations
LocationsLocations
Sylvian fissue/middle fossaSylvian fissue/middle fossa 49%49%yyCerebellopontine angleCerebellopontine angle 11%11%Quadrigeminal cisternQuadrigeminal cistern 10%10%Quadrigeminal cisternQuadrigeminal cistern 10%10%VermianVermian 9%9%Sellar/suprasellarSellar/suprasellar 9%9%InterhemisphericInterhemispheric 9%9%
• Spine - most commonly in Thoracic region• Typically dorsalTypically dorsal• Extra- or intra-dural
OutlineOutlineOutlineOutline
EpidemiologyEpidemiologyPresentationPresentationLocationsLocationsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsPathologyPathologyTreatmentTreatment
Radiographic AppearanceRadiographic AppearanceRadiographic AppearanceRadiographic Appearance
CT:CT: wellwell--demarcated cystic massdemarcated cystic massCT:CT: wellwell demarcated cystic massdemarcated cystic massExtraExtra--axial axial –– exerts mass effectexerts mass effectCSFCSF like densitylike densityCSFCSF--like densitylike densityNo enhancementNo enhancementE pands/remodels boneE pands/remodels boneExpands/remodels boneExpands/remodels boneIntracystic hemorrhage Intracystic hemorrhage –– hyperdense (rare)hyperdense (rare)
CTA:CTA: MCA vessels posteriorly displacedMCA vessels posteriorly displaced
Radiographic AppearanceRadiographic AppearanceRadiographic AppearanceRadiographic Appearance
MRI:MRI: wellwell--demarcated cysticdemarcated cysticMRI:MRI: wellwell demarcated, cysticdemarcated, cysticT1WI and T2WI: isointense to CSFT1WI and T2WI: isointense to CSFNo enhancementNo enhancementNo enhancementNo enhancement
Fl iFl i S dS dFlair:Flair: SuppressedSuppressed
DiffusionDiffusion--weighted:weighted: No restrictionNo restriction
Radiographic AppearanceRadiographic AppearanceRadiographic AppearanceRadiographic Appearance
CTCT--MyelogramMyelogramCTCT MyelogramMyelogramMay or may not communicate with May or may not communicate with subarachnoid spacesubarachnoid spacesubarachnoid spacesubarachnoid spaceLargely replaced by MRILargely replaced by MRIMore important for spinal arachnoid cystsMore important for spinal arachnoid cystsMore important for spinal arachnoid cystsMore important for spinal arachnoid cysts
Galassi ClassificationGalassi ClassificationMiddle fossa arachnoid cystsMiddle fossa arachnoid cysts
Type I:Type I: small, lenticular; small, lenticular; ypyp , ;, ;located at temporal pole;located at temporal pole;
Communicates with subarachnoid Communicates with subarachnoid spacespace
Type II:Type II: involves anterior and involves anterior and intermediate segments of intermediate segments of Sylvian fissue; quadrangularSylvian fissue; quadrangularSylvian fissue; quadrangularSylvian fissue; quadrangular
Partially communicates with Partially communicates with subarachnoid spacesubarachnoid space
Type III:Type III: entire Sylvian fissue, entire Sylvian fissue, bony expansion of middle bony expansion of middle fossa; mass effectfossa; mass effect
Mi i l i ti ithMi i l i ti ithMinimal communication with Minimal communication with subarachnoid spacesubarachnoid spaceMarked shiftMarked shift
Arachnoid CystsArachnoid CystsImaging Imaging –– Middle FossaMiddle Fossa
Elevation of lesser sphenoid wing, thinning of squamous bone
Frontal displacement of greater wing
Arachnoid CystsArachnoid CystsImaging Imaging –– Middle FossaMiddle Fossa
Type IType I
• Rarely treated
Arachnoid CystsArachnoid CystsImaging Imaging –– Middle FossaMiddle Fossa
Type I
Arachnoid CystsArachnoid CystsImaging Imaging –– Middle FossaMiddle Fossa
Type II Treat if symptomatic
Arachnoid CystsArachnoid CystsImaging Imaging –– Middle FossaMiddle Fossa
Type IIIType IIIComplete re-expansion frequently not achieved
Arachnoid CystsArachnoid CystsImaging Imaging -- CTCT
Arachnoid CystsArachnoid CystsArachnoid CystsArachnoid CystsImaging Imaging –– Sellar/suprasellarSellar/suprasellar
Frequently present with obstructive hydrocephalus, visual impairment, and endocrinopathies
Arachnoid CystsArachnoid CystsImaging Imaging –– Cerebellopontine angleCerebellopontine angle
Arachnoid CystsArachnoid CystsImaging Imaging –– Quadrigeminal and ClivalQuadrigeminal and Clival
Obstructive hydrocephalus
Arachnoid CystsArachnoid CystsImaging Imaging –– VermianVermian
Arachnoid CystsArachnoid CystsImaging Imaging –– Posterior fossaPosterior fossa
Arachnoid CystsArachnoid CystsImaging Imaging –– hemorrhagichemorrhagic
• Intracystic hemorrhage • Acute intracystic hemorrhage y gand subdural hematoma
y gwith fluid-fluid level
S i l A h id C tS i l A h id C tSpinal Arachnoid CystsSpinal Arachnoid Cysts
Arachnoid/Meningeal CystsArachnoid/Meningeal CystsSpine Classification Spine Classification –– Nabors et al., 1988Nabors et al., 1988
Type I: Extradural: No nerve rootsType I: Extradural: No nerve rootsType I: Extradural: No nerve rootsType I: Extradural: No nerve rootsType IA: extradural arachnoid cystType IA: extradural arachnoid cystType IB: sacral meningoceleType IB: sacral meningoceleFib li iFib li iFibrous liningFibrous lining
Type II: Extradural: Roots involvedType II: Extradural: Roots involvedType II: Extradural: Roots involvedType II: Extradural: Roots involvedTarlov cystsTarlov cystsFibrous liningFibrous lining
Type III: Intradural arachnoid cystsType III: Intradural arachnoid cysts+ arachnoid lining+ arachnoid liningggDifferent T2 signal sometimes (no pulsations)Different T2 signal sometimes (no pulsations)
Arachnoid CystsArachnoid CystsSpineSpine
Intradural versus Extradural: EtiologiesIntradural versus Extradural: EtiologiesIntradural versus Extradural: EtiologiesIntradural versus Extradural: Etiologies
Intradural:Intradural: arachnoid diverticulum or adhesion orarachnoid diverticulum or adhesion orIntradural:Intradural: arachnoid diverticulum or adhesion or arachnoid diverticulum or adhesion or trabecular proliferation, either congenital or secondary trabecular proliferation, either congenital or secondary to trauma/infectionto trauma/infection
Extradural:Extradural: associated with a dural defect; ballassociated with a dural defect; ball--valve valve effect causes enlargementeffect causes enlargementeffect causes enlargementeffect causes enlargement
Workup includes MRI followed by CTWorkup includes MRI followed by CT--myelogrammyelogramp yp y y gy g
Arachnoid CystsArachnoid CystsI iI i S iS iImaging Imaging –– SpineSpine
Arachnoid CystsArachnoid CystsImaging Imaging –– SpineSpine
Arachnoid CystsArachnoid CystsImaging Imaging –– SpineSpine
Arachnoid CystsArachnoid CystsImaging Imaging –– SpineSpine
Diff ti l Di iDiff ti l Di iDifferential DiagnosisDifferential Diagnosis
Arachnoid CystsArachnoid CystsImaging Imaging –– Differential DiagnosisDifferential Diagnosis
Differential includes any cystic tumorsDifferential includes any cystic tumorsJPAsJPAsCraniopharyngiomasCraniopharyngiomasHemangioblastomaHemangioblastoma
Also any nonAlso any non--neoplastic cystneoplastic cystAlso any nonAlso any non neoplastic cystneoplastic cystPorencephalic cystPorencephalic cystNeurenteric cystNeurenteric cystNeurenteric cystNeurenteric cyst
Arachnoid CystsArachnoid CystsImaging Imaging –– Differential DiagnosisDifferential Diagnosis
Primary differential: epidermoid cystsPrimary differential: epidermoid cystsPrimary differential: epidermoid cystsPrimary differential: epidermoid cysts
Epidermoid CystsEpidermoid CystsImaging Imaging –– Differential DiagnosisDifferential Diagnosis
Arachnoid vs Epidermoid Cysts Arachnoid vs Epidermoid Cysts Differentiate with FLAIR and DWIDifferentiate with FLAIR and DWI
Epidermoid Arachnoid cystp y
Arachnoid CystsArachnoid CystsImaging Imaging –– Differential DiagnosisDifferential Diagnosis
Arachnoid cyst versus
mega cisterna magna
• ACs have mass effect
AC Mega CM
OutlineOutlineOutlineOutline
EpidemiologyEpidemiologyPresentationPresentationLocationsLocationsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsPathologyPathologyTreatmentTreatment
PathologyPathologyPathologyPathology
Gross:Gross: thin, thin, translucent cyst wall translucent cyst wall filled with CSFfilled with CSF
PathologyPathologyPathologyPathology
Microscopic:Microscopic: cystcystMicroscopic:Microscopic: cyst cyst lined by flattened lined by flattened arachnoid cellsarachnoid cells
Sometimes with Sometimes with proliferated trabeculaeproliferated trabeculae
OutlineOutlineOutlineOutline
EpidemiologyEpidemiologyPresentationPresentationLocationsLocationsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsImaging CharacteristicsPathologyPathologyTreatmentTreatment
TreatmentTreatmentTreatmentTreatment
Controversial:Controversial:
Shunting versus excision/fenestrationShunting versus excision/fenestration
TreatmentTreatmentShuntingShunting
Pros:Pros:Pros:Pros:easy to performeasy to performimmediate cyst decompressionimmediate cyst decompression
Cons:Cons:Frequently need to shunt both ventricle and cystFrequently need to shunt both ventricle and cystInfectionInfectionRecurrenceRecurrenceRecurrenceRecurrenceVisualization Visualization –– bridging veinsbridging veinsSlitSlit--cyst syndrome (symptoms of elevated ICP but cyst syndrome (symptoms of elevated ICP but decompressed cyst)decompressed cyst)
TreatmentTreatmentExcision/fenestrationExcision/fenestration
Goal: Goal: decompression with shuntdecompression with shunt--independenceindependencepp pp
Pros:Pros:R l ti lR l ti lRelatively easyRelatively easyNo foreign material implantedNo foreign material implantedExcellent visualizationExcellent visualization
Cons:Cons:Some increased recurrence rate depending onSome increased recurrence rate depending onSome increased recurrence rate depending on Some increased recurrence rate depending on techniques (scarring, adhesions)techniques (scarring, adhesions)May still require shuntingMay still require shunting
TreatmentTreatmentExcision/fenestrationExcision/fenestration
Techniques:Techniques:Techniques:Techniques:Open craniotomyOpen craniotomy
Endoscopic fenestrationEndoscopic fenestrationM t ff ti f ll t ithM t ff ti f ll t ithMost effective for suprasellar cysts, esp. with Most effective for suprasellar cysts, esp. with opening of lamina terminalisopening of lamina terminalis
Keyhole craniotomyKeyhole craniotomyRecently shown to be very effective: 80Recently shown to be very effective: 80--95%95%Recently shown to be very effective: 80Recently shown to be very effective: 80--95% 95% success rate with middle fossa cystssuccess rate with middle fossa cysts
TreatmentTreatmentExcision/fenestrationExcision/fenestration
Pre-op Post-op
TreatmentTreatmentSpinal arachnoid cystsSpinal arachnoid cysts
Laminectomy and excisionLaminectomy and excision
Closure of dural defect with extradural Closure of dural defect with extradural cystscystscystscysts
May also require shunting (intradural)May also require shunting (intradural)
H Th k i iH Th k i iHappy ThanksgivingHappy Thanksgiving