Pathology of Brain Spinal Cord Tumours

8/6/2019 Pathology of Brain Spinal Cord Tumours

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a o ogy o ra n p na or umours

Causes of Brain TumoursHereditary, genetic influencesIonizing radiationsHead injuriesDiet N nitrosoamines

Major Classes of Brain TumoursGliomasAstrocytomasOligodendrogliomaEpendymomaNeuronal Tumours

Ganglion cell tumoursTumours with only neuronal elementsPoorly Differentiated Neoplasms/ EmbryonalMedulloblastomaOther Parenchymal TumoursLymphomasGerm cell tumoursMeningiomasMetastatic Tumours

Spinal Cord Tumours10% Primary spinal cord tumours originate in cells within spinal cordThe rest originate in cells next to spinal cordEg. Tumours develop on spinal nerve roots(parts of spinal nerves that emerge from spinal cord)Peripheral Nerve Sheath TumoursSchwannoma

NeurofibromaMalignant peripheral nerve sheath tumour (MPNST)Neurofibromatosis (Type 1, Type 2)



trocytomase from astrocytes (neuroglial cells)count for 80% of primary Intracranial Tumours (ICTS) in adultses Cerebral hemispheresnical features

HeadachesSeizuresFocal neurologic deficits (anterior/ middle)

rocytomaGrade I

Pilocytic astrocytoma

Grade II

Diffuse astrocytoma

Grade III

A naplastic astrocytoman in kids with cellularity Nuclear atypia Nuclear atypia

Mitotic activity

% of all gliomasst common gliomas in children t 2 decades of lifes

Posterior fossa (67% arise in cerebellum)Optic chiasm/ hypothalamusCerebral hemispheresSpinal cord ( frequent)

10-15% of all astrocytic brain tumoursTypically affects young adults (30-40 y/o)Male : Female = 2:1Tumour occurs throughout CNS(preferentially supratentorial area )(most common location frontal, temporal)Characteristicsy Degree of cellular differentiationy Slow growthTendency for malignant progression Grade III, Grade IV

AdultsPreferentially in cerebral hemisphereMay arise from astrocytoma Grade II or de novoTendency to progress to Grade IV

nical Featuresal neurological deficits/ non-localizing signs

Headache ICP

zuresual loss

Fibrillary A strocytomaCerebral hemisphere is commonest siteDiffuse in naturePresent withy Seizuresy Headachesy Focal neurological deficits (related to site of involvement)

gnosisellent prognosis

Grow very slowlyPatients survive > 40 years after incomplete resection

ion may eventually prove fatal

Gemistocytic A strocytomaPresence of conspicuous germistocytic neoplastic astrocytesAt least 20% of all tumoursGFAP +ve

Protoplasmic A strocytomaRare variant

CellularityMucoid degenerationMicrocyst formationNuclei uniform, round to ovalMitosis absentGenetic alterations found in gr ade astrocytomaInactivation of p53Over expression of PDG F -A receptor

Disruption of BBBAmplification of epidermal growth factor receptor(Genetic alteration lead to transition of Grade Grade)



trocytoma (cont.)Grade I

Pilocytic astrocytomaGrade II

Diffuse astrocytomaGrade III

A naplastic astrocytoma

in Stem Gliomaade 1)rse possible location

nnot be resected

Pilocytic astrocytoma

Cystic, Tumour nodule in wallof cyst Diffuse astrocytoma

Diffuse , poorly defined, grey,infiltrative tumourExpands & distorts brainparenchymaCut surface firm, soft, gelatinous,areas of cystic degeneration

Fibrillary astrocytoma

A naplastic astrocytoma A naplastic astrocytoma

ocytic astrocytomaw to moderate cellularityolar astrocytes

ng hair-like processes crocysts, loose areas

Fibrillary astrocytomaF ibrillary neoplastic astrocytesNuclear atypia enlargement

Cigar-shaped nucleiHyperchromatic nucleiMitosis is rareGood prognosis

Fibrillary astrocytomaF ibrillary neoplastic astrocytes

Nuclear atypia enlargementCigar-shaped nucleiHyperchromatic nucleiMitosis is rareGood prognosis

A naplastic astrocytoma Cellularity

Distinct nuclear atypia Mitosis

A naplastic astrocytomaMore densely cellularGreater nuclear pleomorpis

Mitotic activity seen

ocytic astrocytomaenthal fibersaline, eosinophilic, round/ oval/ irregular proteinaceous material

glial processes)od prognosis if combination of

Rosenthal fibers Micro-cysts Calcification

Gemistocytic astrocytomaPlump, glassy, angular shapeEosinophilic cell bodies

Eccentric nuclei

Protoplasmic astrocytoma

CellularityMucoid degenerationMicrocyst formationNuclei uniform, round to ovalMitosis absent

A naplastic astrocytomaVascular proliferation

A naplastic astrocytomaVascular proliferation



OligodendrogliomaWHO Grade II Compromise of y 5-6% of Gliomasy 2.5% of all primary brain tumoursArise in cerebral white matter & cortex Commonest is frontal region (50-65%)Followed byy Temporal lobey Parietal lobey Occipital lobeAge adults (40-45 y/o)Rare in children

Male :F

emale = 1.1:1Present with seizures & other neurological complaintsGenetic alterationsy Loss of heterozygosity on chromosome 1p, 19qy Loss of 9p and/or 10qGenetic alterations predict outcome of diseaseGrows slowlyPrognosis better than Astrocytomay Average survival 5-10 yearsy With modern therapeutic approachesMorphology

OligodendrogliomaWell circumscribedGelatinousGray massesFoci of haemorrhageCystic changesCalcification

OligodendrogliomaWell circumscribedGelatinousGray massesFoci of haemorrhageCystic changesCalcification

OligodendrogliomaRounded nucleiHalo of clear cytoplasm ( fried egg appearance )

Scattered foci of calcifications ( psammoma bodies )

EpendymomaWHO Grade II Arise from ependymal lining of ventricles/ central canal of spinal cordArise iny 4 th ventricle in children , young adultsy Spinal cord in middle aged4th ventricle tumours cause hydrocephalus (cannot be completely removed)CSF dissemination may occurGenetic alterationy Alteration on chromosome 22y Absence of mutations in p53Age range from 1 month 81 years oldFemale : Male = 1:1

Average survival 4 yearsPrognosis is poorMorphology

EpendymomaSolidPapillary masses(extending from floor of ventricle)Clearly demarcated

Ependymoma

EpendymomaHighly cellularTumour cells regular round to oval nucleiSalt & pepper chromatinAbundant granular chromatinArranged in papillary frondsWell differentiatedEpendymal rosettesPerivascular pseudorosettes



Ganglion Cell TumoursWHO Grade I Slow growing tumoursCommon sitesy Floor of 3 rd ventricley Hypothalamusy Temporal lobe

Gangliocytoma GangliogliomaEntire tumour is composed of ganglion cells

Tumour contains admixture of ganglion cells, glial neoplasm

MorphologyWell circumscribed massesFocal ca lcifications

Cysts

GangliocytomaNeoplastic ganglion cells (seen in clumps)Separated by acellular stroma

GangliogliomaScattered, small clusters of ganglion cellsAssociated with a glioma

MedulloblastomaWHO Grade IVPredominant in children Second ICT of childhood (after astrocytomas)Highly malignantOccurs exclusively in cerebellum Derived from fetal external granular layer of cerebellumGrows rapidly & occludes CS F flow Hydrocephalus Seeds through CS F Implants around spinal cord, cauda equina(need irradiation of whole Neuraxis)Does not express phenotypic markers of mature cells of nervous systemGenetic alteration Loss of material from short arm of chromosome 17Highly malignant (yet radiosensitive )5 year survival 75%Morphology

Solid, grayish, friable tumourSmall foci of necrosis Extend to surface of brainMay involve leptomeninges

Extremely cellular, sheets of densely packed tumour cellsCells are small, blue, elongated nuclei ( carrot-shaped cells)Scanty cytoplasmMitoses are abundantHomer-Wright rosettes



CNS Lymphoma

Primary CNS Lymphomas Secondary CNS Lymphomas1% of ICTsCNS Neoplasm iny AIDSy ImmunosuppressedDeep within cerebral hemispheres Bilateral (commonly)Lymphoma cells exhibit anangiocentric distributionB-cell l ymphomasEBV-related

Lymphomas arising outside CNSRarely involve brain parenchymaMay involvey Meningesy Intradural spinal nerve rootsy Epidural space

Primary CNS Lymphoma

MeningiomasBenign tumour in adults Females (more frequent)Arise from meningothelial (arachnoidal) cells Typically attached to inner surface of dura mater Present with (due to compression effects)y Vagus non-localizing symptomsy Focal symptomsCommon site of involvementy Parasaggital aspect of brainy Wing of sphenoidy Olfactory grooveGenetic alterationy

Loss of chromosome 22qy Mutations of neurofibroma type 2 geneMorphology

MeningiomaBeneath duraCompressed underlying

cerebral hemisphere

MeningiomaBenign meningiomaBeneath dura

MeningiomaSolid rounded massWell defined dural baseCompress underlying brain(easily separated from it)May extend into overlying skull boneAppear as plaque spreading insheet-like fashion

Other Variants IncludeSyncytialFibroblasticTransitionalPsammomatousSecretoryAtypical meningioma (II/ IV)Anaplastic (malignant) meningioma(III/ IV)

MeningiomasMeningothelial cells arranged in whorls Plump, round-to-oval nucleiModerate amount of cytoplasmIndistinct cytoplasmic borders



Metastatic TumoursMostly carcinoma 25% of brain tumoursCommonest primary sitesy Lungy Breasty Kidneyy Skiny GITMorphology

Metastatic TumoursSpace occupying lesions(clinical feature depend on site involved)

Metastatic Tumours

Metastatic Tumours



SchwannomaBenign tumours arising from Schwann cellPresent with compression symptoms Common locationy Flexor surface of extremitiesy Necky RetroperitoneumAssociated with mutation of N F2 gene (chromosome 22)

Morphology

SchwannomaWell circumscribed , encapsulated massAttached to nerve (can be separated from it)F irm, grey whiteAreas of cystic change

A ntoni A A ntoni BHypercellular pattern of growthelongated cellsArranged in fascicles with littlestromal matrixVerrucae bodies (nucleus free zones)

Less densely cellularMicrocystsMyxoid changes

NeurofibromaCan occur iny Skin (cutaneous neurofibroma)y Peripheral nerve (solitary neurofibroma)In skin, may be solitary or multiple (plexiform neurofibroma)Sometimes assoc. w. loss of Neurofibroma 1 genePresent with symptoms of nerve compression Types

Neurofibromatosis Type 1 Neurofibromatosis Type 2Autosomal dominantCharacteristicsy Neurofibromasy Gliomas of optic nervey Pigmented nodules of irisy Cutaneous hyperpigmented

maculesMutation of N F1 gene on 17q 11

Autosomal dominantCharacteristicsy Bilateral 7 th nerve

schwannomay

Multiple meningiomay Ependymoma of spinal cordMutation of N F2 gene on 22q 12

Morphology

Neurofibroma

NeurofibromaUnencapsulated massesWavy spindle shaped cellsMyxoid collagenous stromaInterspersed nerve fibers

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Pathology of Brain Spinal Cord Tumours