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1、PRIMARY INTRACRANIAL NEOPLASMS,Monika Arora,MS 4Lyudmila Morozova,MS 4,Imaging for Brain Tumors1,Skull X-rays:Rarely necessary.Useful in demonstrating calcification,erosion,or hyperostosisCT:Most widely used for diagnosis of brain tumorsWill detect 90%of tumors,but might miss:Small Tumors(0.5 cm)Tum
2、ors Adjacent to bone(pituitary adenomas,clival tumors,and vestibular schwannomas)Brain Stem Tumors Low Grade AstrocytomasMore sensitive than MRI for detecting acute hemorrhage,calcification,and bony involvementMRI:Preferred for follow-up of most brain tumorsMore sensitive than CT scansCan detect sma
3、ll tumorsProvides much greater anatomic detail Especially useful for visualizing skull base,brain stem,&posterior fossa tumors,Infratentorial vs Supratentorial Tumors,SUPRATENTORIAL TUMORS3,MeningiomasGliomasAstrocytomasGlioblastoma MultiformeOligodendrogliomasGerminomasColloid Cysts of Third Ventri
4、cle,MENINGIOMA1,2,3,Epi:2nd most common primary brain tumor after gliomas,incidence of 6/100,000 Usual age 40-70FMFacts:Arise from arachnoidal cap cell type from the arachnoid membraneUsually non-invasive Associated with NF-2Location:Parasagittal region Sphenoid wingParasellar regionPresentation:Asy
5、mptomatic Symptomatic:focal or generalized seizure or gradually worsening neurologic deficit,MENINGIOMA1,On ImagingCT:isodense or hypodense,homogenous extra-axial mass with smooth or lobulated,clearly demarcated contours which enhance homogenously and densely with contrastFrequently have areas of ca
6、lcification and produce hyperostosis of adjacent bone.,MRIIsointense with gray matter on T1 imagesEnhance with contrast often with enhancing dural trail extending from the tumor attachment,GLIOMAS Arise from Glial Cells,AstrocytomasAstocytomas fall on a gradient that ranges from benign to malignantO
7、ligodendrogliomas,Low Grade Pilocytic Astocytomas,Glioblastoma multiforme,Benign,Malignant,Diffuse Low Grade Astrocytomas,ASTROCYTOMA1,2,3:Diffuse Low Grade Astrocytoma,Epi:15%of AstrocytomasYoung AdultsFacts:Widely Infiltrate surrounding tissueLocation:Frontal RegionSubcortical white matterPresenta
8、tion:SeizuresHeadacheSlowly progressive neurologic deficitsOn Imaging:CT:Well circumscribed,non enhancing,hypodense or isodense lesion MRI:MRI more sensitive than CT useful for identification and establishing extentT1 image shows abnormal areas of decreased signalT2 image shows abnormal areas of inc
9、reased signalUsually no enhancement,Cyst,T1 weighted,T2 weighted,ASTROCYTOMA1,2,3:High Grade Astrocytoma:Glioblastoma,Epi:Most common type of primary brain tumor in adultsAge of presentation:40-60,MFFacts:May arise de novo or evolve from a low-grade glioma Tumor infiltrates along white matter tract
10、and can cross corpus callosumPoor PrognosisCan look like a butterfly lesionLocation:Frontal&Temporal Lobes Basal GangliaPresentation:Seizures,HeadacheSlowly progressive neurologic deficits,ASTROCYTOMA1:High Grade Astrocytoma:Glioblastoma,On Imaging:VariableCT:Hypodense or Isodense Central hypodense
11、area of necrosis surrounded by thick enhancing rimSurrounding edemaMRI:T1 image shows low signal intensityT2 image shows high signal intensity,OLIGODENDROGLIOMA1,2,3,Epi:5-10%of primary brain tumorsMean age of onset 40 yearsFacts:Distinguished pathologically from astrocytomas by the characteristic“f
12、ried egg”appearance.Arises from MyelinLocation:Superficially in Frontal LobesPresentation:Seizures most commonHeadacheSlowly progressive neurologic deficits,OLIGODENDROGLIOMA1,On Imaging:CT:Well circumscribed,hypodense lesions with heavy calcificationCystic degeneration is common but hemorrhage&edem
13、a are uncommonMRI:Hypointense or isointense on T1-weighted imagesHyperintense on T2-weighted images with variable enhancement,GERMINOMA1,2,3,Facts:Germ Cell TumorsCauses Parinauds Syndrome disorder characterized by fixed upward gazeLocation:Commonly in Pineal Region(50%)Overlies tectum of midbrainPr
14、esentation:Obstructive Hydrocephalus due to aqueductal stenosisOn Imaging:CT Isodense or hyperdense Enhances with contrastMRIIsointense or Hypointense on T1-weighted images&enhance with gadoliniumHyperintense on T2 images,T1 Images,COLLOID CYST OF THE VENTRICLE4,Epi:Usually in Adults1%of all intracr
15、anial tumorsFacts:Managed SurgicallyCauses hydrocephalus by obstructive flowEndodermal originLocation:Foramen of MonroAnterior aspect of third ventriclePresentation:HeadachesVertigoMemory deficits,COLLOID CYST OF THE VENTRICLE,On Imaging:CT:Smooth,round lesions lesion hyperdense to brain tissueThin
16、rim of enhancement after IV contrastMRI:T1-weighted hyperintense lesion due to proteinaceous nature.T2-weighted shows hypointense lesion,INFRATENTORIAL TUMORS1,Choroid plexus papillomasCerebellar astrocytomasMedulloblastomasHemangioblastomasEpendymomasBrainstem gliomasSchwannomasPituitary adenomasCr
17、aniopharyngiomas,CHOROID PLEXUS PAPILLOMAS1,2,3,EpiRepresents 2%of gliomasOne of the most common brain tumors in patients 2 years of age;FactsBenign tumor;PresentationHeadacheHydrocephalus secondary to CSF overproductionLocationOccur in decreasing frequency:4th,lateral,and 3rd ventricles;ImagingCT:O
18、ften calcified&enhanced with contrast,CEREBELLAR ASTROCYTOMA1,2,3,Epi:Most often occurs in childhoodFacts:Most potentially curable of the astrocytomasLocation:Posterior FossaPresentation:Headaches Nausea/VomitingGait UnsteadinessPosterior head tilt with caudal tonsillar herniationOn Imaging:CT or MR
19、I:Tumor arising from vermis or cerebellar hemispheresLarge cyst with single enhancing mural nodule,Cyst,MEDULLOBLASTOMAS1,2,3,EpiRepresent 7%of primary brain tumors2nd most common posterior fossa tumor in children70%of patients are diagnosed prior to age 20 with peak incidence between 5-9 years of a
20、ge;FactsPrimitive neuroectodermal tumors(PNET)(or not?)Soft,friable tumors,often necroticCan metastasize via CSF tractsHighly radiosensitive LocationAbout 75%arise within the cerebellar vermisPresentationMost frequently present with signs of intracranial pressureCranial nerve deficits may also occur
21、,MEDULOBLASTOMAS1,2,3,ImagingMRI reveals a contrast-enhancing midline or paramedian tumor which often compresses the 4th ventricle;Gadolinium enhancement will most likely be heterogeneous and may show evidence of necrosis,hemorrhage,or cystic change;,HEMANGIOBLASTOMA1,2,3,Epi2%of primary intracrania
22、l tumors and 10%of posterior fossa tumorsMost found in young adults and childrenFactsCharacterized by abundant capillary blood vesselsIf found in cerebellum and retina,may represent part of von Hippel-Lindau syndrome.Acute hemorrhage can be fatal15-20%of patients with hemangioblastomas can present w
23、ith erythrocytosisPresentationUsually present with neurologic deficits by direct compression or hemorrhageNeurologic deficits may include cerebellar ataxia,oculomotor nerve dysfunction,motor weakness,or sensory deficitsLocationMost often found in cerebellum and spinal cord,HEMANGIOBLASTOMAS1,2,3,Ima
24、gingGadolinium-enhanced MRI is the technique of choice to diagnose hemangioblastomas;Seen as an enhancing nodule associated with a cyst located in cerebellum.,EPENDYMOMAS1,2,3,EpiAccounts for 10%of CNS lesions;Male=FemaleMedian age at diagnosis is 5 years oldFactsDerived from primitive gliaOverall s
25、urvival at 10 years is 45-55%PresentationMost patients present with symptoms of increased intracranial pressureLocationTypically arise within or adjacent to the ependymal lining of the ventricular system.In children,90%are intracranial with 60%arising in posterior fossa(4th ventricle is the most com
26、mon infratentorial site)Most common spinal cord glioma(in adults,75%arise within spinal cord);,EPENDYMOMA1,2,3,ImagingUsually well demarcated with frequent areas of calcification,hemorrhage,and cysts;CT:Appear hyperdense with homogeneous enhancementMRI:ependymomas have a hypointense appearance on T1
27、 and are hyperintense on T2;,SCHWANNOMAS1,2,3,EpiFemalemaleMedian age at diagnosis is 50Account for 80-90%of cerebellopontine angle tumorsComprise 8%of intracranial tumors in adults;rare in children(except with NF-2)FactsUnilateral in 90%of cases(R=L);Bilateral acoustic neuromas are diagnostic of NF
28、-2;PresentationPatients may present with asymmetric sensorineural hearing loss,tinnitusFluctuating unsteadiness while walking,vertigo(although only 1%of patients with vertigo had schwannomas);If CN V nerve is affected,facial numbness,pain,and hyperesthesia may be present;If CN VII is affected,facial
29、 paresis may be present.Tumor progression may lead to compression of brainstem or cerebellum leading to ataxia,tonsil herniation,and hydrocephalusLocationArise from vestibular division of CN VIII;majority benign,SCHWANNOMAS1,2,3,ImagingMRI:with gadolinium is more sensitive in detection of Schwannoma
30、s(when compared to CT);it can detect tumors as small as 1-2 mm;seen as enhancing lesion in the region of CPA;Fine-cut CT through internal auditory canal can detect large or medium tumors.,PITUITARY ADENOMAS1,2,3,EpiMost common tumors of pituitary glandRepresent 8%of primary brain tumorsFactsOut of p
31、ituitary adenomas,prolactinomas are the most common;PresentationMay cause hypopituitarism and visual field defects;Patients should have endocrine,radiographic,and ophthalmologic assessments.,PITUITARY ADENOMAS1,2,3,Imaging:Plain x-ray may show an enlarged sella turcica;CT scan will detect only large
32、 adenomas;it will show a large hyper-or isodense lesion;MRI is the imaging of choice;Microadenomas(lesions 1 cm)will be seen as a low intensity lesions on T1;Gadolinium will enhance the normal gland that is adjacent to adenomaMacroadenomas will appear as isointense on T1 and will enhance uniformly w
33、ith gadolinium,CRANIOPHARYNGIOMAS1,2,3,EpiRepresent 1-3%of primary brain tumorsBimodal distribution:first peak infants and children;second peak 55-65 year oldFactsDerived from epithelial remnants of Rathkes pouch;slow growing;benignTend to recur even after“complete”removal20-year survival rate of ch
34、ildren with craniopharyngiomas is about 60%.LocationLocated in suprasellar fossa and inferior to optic chiasmPresentationCause bitemporal hemianopsia and hypopituitarism;frequently present with headache;,CRANIOPHARYNGIOMAS1,2,3,ImagingCystic calcified parasellar lesion could be seen on radiograph;,B
35、RAINSTEM GLIOMAS1,2,3,EpiMale=FemaleAccount for 10-20%on all CNS tumorsMore common in children(account for 20%of all intracranial neoplasms under the age 15);In children,median age at diagnosis is 5-9 years of age.FactsNF-1 is the only known risk factorMostly benign(but range from benign to very agg
36、ressive);Long term survival for low-grade gliomas is near 100%.LocationIn peds,80%arise in pons,with 20%arise in medula,midbrain,and cervicomedulary junction;PresentationMost patients with low-grade brainstem gliomas have a long history of minor signs and symptoms;May present with neck pain or torti
37、collis;Medulary tumors may present with cranial nerve palsies,dysphagia,nasal speech and apnea,n/v,ataxia,or weakness;May cause“locked-in”syndrome,BRAINSTEM GLIOMAS1,2,3,ImagingMRI is the method of choice to image those tumors(brainstem glioma appears isodense on CR and can be missed);Appear isointe
38、nse or hypointense on T1 images,hyperintense on T2,and inhance uniformly and brightly with IV contrast;,Now Test Yourself by Playing:Name that Tumor,Name that Tumor,May present with endocrine abnormalities,Presents with bilateral temporal hemianopsia,Answer:Pituitary Adenoma,Name that Tumor,Age 40-6
39、0,Very Malignant“Butterfly Lesion”,Answer:Glioblastoma,Name that Tumor,Unilateral in 90%of cases,Bilateral lesions seen almost exclusively in NF2,Answer:Schwannoma,Name that Tumor,Bimodal distribution,Derived from Rathkes pouch,Answer:Craniopharyngioma,Name that Tumor,2nd most common brain tumor,Ari
40、ses from arachnoid cap cells,Answer:Meningioma,Name that Tumor,Slow growing,Arises from Myelin,Answer:Oligodendoglioma,Name that Tumor,Most likely a PNET tumor,Highly radiosensitive2nd most common tumor in children,Answer:Medulloblastoma,Name that Tumor,Overlies tectum&midbrain,Can cause obstructive
41、 hydrocephalus due to aqueduct stenosis,Answer:Pineal Germinoma,Name that Tumor,Usually benign,Most common in young children,Answer:Low grade pilocytic astrocytomas,Name that Tumor,Can Cause Locked-In syndrome,NF-1 is the only known risk factor,Answer:Brainstem Glioma,Name that Tumor,Most often foun
42、d in 4th ventricle,Median age at diagnosis is 5 years old;,Answer:Ependymoma,Name that Tumor,Characterized by abundant capillary blood vessels;,Associated with Retinal Lesions,Answer:Hemangioblastoma,Name that Tumor,Usually occurs in young adults,15%of astrocytomas,Answer:Diffuse Low Grade Astrocyto
43、mas,T2 weighted Image,References,Wen,P.,Teoh,S.,Black,P.Clinical,imaging,and laboratory diagnosis of brain tumors.Online http:/UptoDate Online 2007Fix,J.(2001).Neuroanatomy.3rd edition.Lippincott Williams&Wilkins.Iaia,A.,Hsu,L.,(1996).Colloid Cyst of Third Ventricle.Online http:/brighamrad.harvard.edu/Cases/bwh/hcache/51/full.html,
