intra axial posterior fossa tumor

INTRA AXIAL POSTERIOR FOSSA TUMORS

INTRA AXIAL POSTERIOR FOSSA TUMORS

DR PRAVEEN K TRIPATHI

02-Mar-161

Posterior fossa - OutlineCalvariumPosterior skull baseBrainstem anteriorlyMidbrain, pons and medullaCerebellum posteriorly2 Hemispheres and midline vermisDivided into:Mesencephalon (midbrain)Rhomboencephalon (pons, medulla and cerebellum)Cerebral aquaduct and fourth ventricleCSF cisterns containing vertebrobasilar arteries and veins

02-Mar-162

Background Posterior fossa tumors are more common in children than the adults.Primary brain tumors are the most common solid tumors in the pediatric population, comprising 20% to 25% of all childhood cancers. About 60% to 70% of all pediatric brain tumors originate in the posterior fossa. About 15-20% of brain tumors in adults occur in the posterior fossa. Hydrocephalus is common in children with posterior fossa tumors, occurring in 71% to 90% of pediatric patients02-Mar-163

Brain Tumors - BackgroundPrimary brain tumor 6 persons/100000/year Metastatic brain tumor 6 persons/100000/year 1 in 15 primary brain tumors occur in children under 15 years 20-30% of cancers in children 2500-3000 new diagnoses/year 2nd most common neoplasm Most occur before age 10 years Male/Female = 1.3/1.0 60-70% 5 year survival

02-Mar-164

Aetiology No specific

Genetic Environmental02-Mar-165

Classification

02-Mar-166

Extra-axial LesionVestibular schwannomaMeningiomaEpidermoidMetastasesTrigeminal neuromaFacial nerve neuromaArachnoid cyst02-Mar-167

Intra-axial Post Fossa Tumors-adults 02-Mar-168

Intra-axial Post Fossa Tumors-pediatrics 02-Mar-169

Posterior Fossa & Brainstem Tumors - Clinical Features02-Mar-1610

MetastasesMC post fossa tumor in adultsCerebellum is a common site16% of cases of solitary brain metsPrimaryLung 44%Breast 10%Kidney (renal cell) 7%GI 6%Melanoma 3%Undetermined 10%

02-Mar-1611

PathologyRounded solid partially cystic mass edemaAgeRare in children, most common in older adults (> 40 years)LocationAnywhere: grey white junction most common siteImagingNECT: Iso / hyperdense; Ca++ rare in untreated metastasesCECT: Strong solid/ring enhancementMR: Most hypointense on T1, hyperintense on T2W1, most enhance moderately intensely following contrast administration02-Mar-1612

Mets- images

Axial CT contrast image showing multiple metastasesAxial T2 image showing SINGLE metastases02-Mar-1613

ManagementThe goals of treating brain metastases are to establish a histologic diagnosis, to relieve neurologic symptoms,to provide long-term local disease control.

Mostly palliativeMedian survival of patient 26-32 weeksMedicalCorticosteroidsAnticonvulsants.02-Mar-1614

Considerations in Patient Selectionfor Surgical Removal of Brain Metastases

02-Mar-1615

Surgical ManagementSolitary lesionSurgical excision of solitary lesion:Primary disease quiescent or radioresistantLesion accessible, symptomatic or life threateningFor recurrent small cell lung carcinoma following XRTDiagnosis unknown02-Mar-1616

Multiple LesionsWorse prognosis than solitary lesionUsually treated with XRT without surgerySituations where surgery is done:One particular and accessible lesion symptomatic and/or life threateningMultiple lesions that can all be completely removedStereotactic BiopsyLesions not appropriate for surgeryNot candidates for surgical resectionTo ascertain a diagnosis02-Mar-1617

Stereotactic RadiosurgeryNo mass effect, no hydrocephalusAdvantage: No risk of hemorrhage, infection or mechanical spread of tumor cells, Can be used for 3 or fewer metsDisadvantage: Histological proof not obtained, Cannot be used for lesion > 3 cm02-Mar-1618

Newly diagnosed brain metastasis management flowchart

02-Mar-1619

Median survival following craniotomyMonthLung11Breast11Colon8Kidney12Melanoma6.5Miscellaneous11Sarcoma6Urologic (testis, Bladder, Prostate)10Unknown10Esophagus4

Median survival even with best treatment is only 8 months02-Mar-1620

Hemangioblastoma (HGB)Most common primary intra-axial posterior fossa tumor in adults (7-12% of post fossa tumors)Highly vascular well circumscribed solid or cystic neoplasm of CNS or retinaMay occur sporadically (4th Decade) or as part of Von Hippel Lindau disease (3rd decade) AssociationsphaeochromocytomamultipleRCCsvon Hippel Lindau (vHL) disease:~45% of those with vHL develop haemangioblastomas~20% of those with haemangioblastoma have vHLpolycythaemia: due to secretion of erythropoietin from lesions

02-Mar-1621

60% cystic with nodule 40% solidGross hemorrhage, calcification necrosis rareAdults with peak during 40 to 60 years, rare in children

Locationintracranial: 87-97%95% in posterior fossa85% in cerebellar hemisphere10% in the cerebellar vermis5% medullaonly rarely do they extend beyond the cerebellum into the cerebellopontine angle5% supratentorially (typically in the optic radiations)cerebral haemangioblastomas are only really seen in patients withvHLspinal: 3-13%

02-Mar-1622

Clinical features of hemangioblastoma Headache (75%) Gait difficulties (55%) Dysmetria (29%) Nausea or vomiting (28%) Nystagmus (13%) Dysarthria (9%) and/or dysphagia (8%) Hydrocephalus (28%)02-Mar-1623

Hemangioblastoma -ImagingCTthe mural nodule is isodense to brain on non-contrast scans with fluid density surrounding cystbright enhancement of the nodule is demonstrated with contrastthe cyst walls do not usually enhance & calcification is not a featureMRIT1hypointense to isointense mural nodule,CSF signal cyst contentT1 C+ (Gd)mural nodule vividly enhancescyst wall does not enhanceT2hyperintense mural noduleflow voidsdue to enlarged vessels may be evident especially at the periphery of the cyst, seen in 60-70% of casesfluid filled cyst, similar to CSFMR perfusion imaging:high rCBV ratiosAngiography (DSA)Enlarged feeding arteries and often dilated draining veins are demonstrated, with a dense tumour blush centrally

02-Mar-1624

Coronal MRI gadolinium image showing cystic hemangioblastoma with a mural nodule

CT showing cystic hemangioblastoma with a mural noduleImaging02-Mar-1625

Hemangioblastoma -Imaging

Sagittal MRI gadolinium image showing a cerebellar and spinal hemangioblastomas

Computed tomography angio showing vascularity of left cerebellar hemangioblastoma02-Mar-1626

TreatmentSurgical resection is the treatment of choice. Generally, resection of hemangioblastomas in patients with VHL disease is indicated only when the lesions producePreop embolisation reduces the vascularityCystic hemagloblastoma require removal of mural nodule. Cyst drainage alone is of no benefit.Stereotactic RadiosurgeryFor asymptomatic HGB > 5 mm diameter if they are cystic or progressing in size during surveillance02-Mar-1627

Radiation TreatmentMay be useful to reduce tumor size or to retard growth in patients who are not surgical candidates for multiple brainstem HGBChemotherapyOngoing phase II trial with Sunitnib, an inhibitor of vascular endothelial growth factor and platelet derived growth factor02-Mar-1628

Medulloblastoma was first described by Bailey and Cushing in 1924, using the terminology spongioblastoma cerebelliOrigin of cells (WHO- PNET) Static- external granular layer Origin from remnant of cells of the external granular layer of the cerebellum. Dynamic neural progenitor cells Transformation of normal undifferentiated progenitor cells of superior medullary velum which migrate to the fourth ventricle.

Medulloblastoma 02-Mar-1629

Medulloblastomas are the most common posterior fossa tumors constituting 6% of all intracranial neoplasms, 12% of all neuroectodermal tumors most common malignant brain tumor in children-30% of all pediatric brain tumors.The first decade of life accounts for more than 50% of these tumors.A third of them occur between the ages of 15 years and 35 years.There is a slight male preponderance.


The majority (85%) arise from the cerebellar vermis and in the minority, they arise laterally from the cerebellar hemisphere. Several cancer predisposition syndromes are associated with medulloblastoma including Gorlins syndrome,Turcots syndrome, Li-Fraumeni syndrome, and Rubenstein-Taybi syndromeCommon chromosomal copy number changes include gain of chromosomes 1q and 7, as well as loss of chromosomes 22, 11, 10q, and 17p.Loss of 17p is observed in up to 50% of cases


Histology Medulloblastoma (Grade 4) Medulloblastoma with extensive nodularity (MOST COMMON)Desmoplastic/nodular medulloblastoma Anaplastic medulloblastoma Large cell medulloblastoma

Medulloblastoma

Cellular, small cells, scant cytoplasm, Homer-Wright rosettesImmuno histochemistryGFAP +EMA

02-Mar-1632

Clinical features Hydrocephalus : raised ICPBehavioral change, listlessness, irritability, vomiting, and decreased social interactions.Headache Double vision. Head tilt : tonsillar herniation below the foramen magnumCerebellar symptoms Brain stem involvementLeptomeningeal dissemination


Examination Increasing head circumference , full anterior fontanelle with widely split cranial sutures.Papilledema 90% of patientsDiplopia and lateral gaze paresisFourth cranial nerve palsy ( should be considered in any patient with a head tilt )NystagmusCerebellar signs ( ataxia > unilateral dysmetria )


MEDULLOBLASTOMACTOn CT, medulloblastomas appear as a mass arising from the vermis, resulting in effacement of the fourth ventricle / basal cisterns and obstructive hydrocephalus.They are usually hyperdense (90%) and cysts formation/necrosis is common (40-50%), especially in older patients. Calcification is seen in 10-20% of cases.Enhancement is present in over 90% of cases and is usually prominentMRIT1hypointense to grey matterT1 C+ (Gd)overall 90% enhance, often heterogeneouslyT2/FLAIRoverall are iso to hyperintense to grey matterheterogeneous due to calcification, necrosis and cyst formationsurrounding oedema is commonDWI/ADC- restricted diffusion (low ADC values)MR spectroscopyelevated cholinedecreased NAAmay show a taurine peak02-Mar-1635

Medulloblastoma

(A) Contrast CT, (B) MRI T1, (C) MRI gadolinium images showing medulloblastoma02-Mar-1636

Spinal imaging At diagnosis (11-71% show dissemination)Within 24 hrs after surgery or 2 weeks post surgery Surveillance imaging at 3-6 months Medulloblastoma 02-Mar-1637

CHANG CLASSIFICATION Medulloblastoma StageFeatureTumor stage T1Less than 3 cm diameter, limited to vermis, roof of fourth ventricle, or hemisphere T2 More than 3 cm diameter, invades one adjacent structure or partially fills fourth ventricle. T3a Invades two adjacent structure or completely fills fourth ventricle with extension into cerebral aqueduct, foramen of Luschka, or formen of Magndie. T3bArises from floor of fourth ventricle or brain stem; fourth ventricle completely filled T4 Spreads to involve cerebral aqueduct, third ventrical, midbrain, or upper cervical spinal cord

Metastasis stage M0No evidence of metastasis M1 Tumor cells in CSF M2 Gross nodular seeding of brain CSF spaces M3 Gross nodular seeding of spinal CSF spaces M4 Extraneural spread

02-Mar-1638

Current staging of medulloblastomaSTANDARD RISK

No residual tumor on postop MRI and negative CSF result5 years survival is >5% and progression free survival = 50%HIGH RISK

Bulky residual tumor > 1.5 cm2 postopDissemination in the brain, spine or CSFWorse prognosis5 year disease free survival is 35-50%02-Mar-1639

Management SteroidsCSF cytology- LP, EVD, Cisternamagna CSF diversion Definitive surgery Adjuvant therapy Medulloblastoma 02-Mar-1640

Management algorithm for medulloblastomaPresenation : MRI Brain and spineSurgical resectionManagement of hydrocephalus> 3 years< 3 yearsStandard riskPoor riskCraniospinal radiationOR Reduced dose radiation with CT on reasarch protocolCranispinal radiation + adjunct CT ( CCNU, cisplatin vincristine or CT on research protocol

Chemotherapy (No standard regimen)

Follow OR Delayed RT till 3 years old

02-Mar-1641

Management.. SurgeryGross Total Resection, if possible (arises from roof of fourth ventricle- soft reddish vascular with some times sugar coating).Brainstem damage should be avoided.Resolution of natural CSF pathways.SURGERY alone : NOT CURATIVE

RADIOTHERAPY : Cornerstone of adjuvant therapy.

54 to 58 Gy - primary site 35Gy - craniospinal axis

02-Mar-1642

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Medulloblastoma Prognostic Factors Age - Younger tend to do worse Extent of resection Non-posterior fossa tumors Non-localized disease Standard risk 70-80% 5 yr survival High risk50%

what are risk groups?02-Mar-1643

Management.. Recurrent Medulloblastoma

Chemotherapy : limited due to chemo resistance in those patients who have previously undergone CTRedosing with RT avoided due to radiation necrosisHigh-dose chemotherapy with autologous SCR or autologous BMR: subject of intense investigationPrognosisAfter craniospinal radiotherapy, children, especially those younger than 7 years, will have significant intellectual compromise5 - year recurrence-free survival rates : 55% - 67%.Most common site : PRIMARY TUMOR SITE02-Mar-1644

44

Ependymoma Predominantly intraventricular and account for 13% of all primary brain tumors. In children, they constitute 9% of intracranial tumors and are third in frequency after astrocytoma and medulloblastoma Peak age - 0-4yrsMale preponderanceChildren 90% in craniumAdults in spinal 02-Mar-1645

EPENDYMOMAMYXOPAPILLARY (WHO Grade 1)SUBEPENDYMOMA (WHO Grade 1)Ependymoma (WHO Grade 2) Cellular Papillary Clear cell TanycyticAnaplastic ependymoma (WHO Grade 3)

02-Mar-1646

Ependymoma .. Imaging

CT Braincoarse calcification is common (50%)cystic areas (50%)solid component iso to hypodenseheterogeneous enhancementa small proportion can have haemorrhage

02-Mar-1647

Ependymoma..MRIOn MRI, heterogeneous secondary to necrosis, hemorrhage and calcification. Heterogenous contrast enhancementPlasticityExtension to the cerebellopontine angle is characteristic of ependymomas02-Mar-1648

MRI gadolinium (A) sagittal, (B) axial images showing fourth ventricular ependymoma02-Mar-1649

Ependymoma

02-Mar-1650

TREATMENTSurgical excision and postoperative irrradiation have been the mainstay of treatment. Radiation therapy is usually administered to children more than 3 years of age after recovery from surgerySurgery and radiation therapy yield 5-year progression-free survival ranging from 60% to 87% after complete resectionThe incidence of dissemination of ependymoma is only 11% to 17%.02-Mar-1651

Ependymoma..INTRA OP- Tumor arises from the floor and is greyish lobulated gritty and firmStaging: No conventional staging criteria.Postoperative MRI is recommended within 48 hours02-Mar-1652

EpendymomaRole of RadiotherapyPost-operative radiation recommended for patients older than 3 years. The dose of radiation for the treatment of ependymoma has traditionally been in the range of 4500 to 5600 cGy.Stereotactic radiosurgery : Therapeutic option in patients with residual, unresectable or recurrent tumor

Role of ChemotherapyMay be useful < 3 years : Delay cranial radiationChildhood intracranial ependymomas : in general chemo-resistant02-Mar-1653

AIIMS Protocol Low Grade

CSF -VE SurgerySurgeryRadiotherapy56Gy / 28# / 5.5 wks(50 Gy followed by a boost of 6 Gy)Surgery followed by CSI and 6 cycles chemotherapy.High grade

CSF + VE

02-Mar-1654

Cerebellar (Pilocytic astrocytoma)10-20% of pediatric brain tumourPilocytic astrocytoma is the most common pediatric central nervous system glial neoplasmA mean age at presentation of 6 to 8 years is foundRarely found in children under 1 year of age or in adults over the age of 40Benign : extremely high survival rate 94% at 10 yearsMost common astrocytoma in children are of a specific type: Juvenile Pilocytic Astrocytoma (JPA): grade I WHO

02-Mar-1655

Cerebellar Astrocytoma

Symptoms: early morning headache and vomitingOriginate in midline, 30% extend into cerebellar hemispheres 25% are solidMalignant transformation is exceeding rareGross total resection is curativeTumors non surgically accessible: stereotactic radiosurgery

02-Mar-1656

cerebellar astrocytomas- Pathology

Most cerebellar astrocytomas are low grade neoplasmsThese are divided into two pathologic entities. Pilocytic astrocytomas are WHO grade I lesions -65% to 85% a biphasic appearance, with compact areas composed mainly of bipolar cells with hair-like projectionsDiffuse astrocytomas are considered as WHO grade II -15% to 35%. fibrillary neoplastic astrocytes on the background of loosely structured tumor matrix.02-Mar-1657

Pilocytic astrocytoma- IMAGING Four predominant imaging patterns :Mass with a nonenhancing cyst and an intensely enhancing mural nodule (21%)Mass with an enhancing cyst wall and an intensely enhancing mural nodule (46%)Necrotic mass with a central nonenhancing zone (16%), and Predominantly solid mass with minimal to no cyst like component (17%) MRISignal characteristics include:T1:iso to hypointense solid component compared to adjacent brainT2:hyperintense solid component compared to adjacent brain

02-Mar-1658

Pilocytic astrocytoma- IMAGINGMRISignal characteristics include:T1:iso to hypointense solid component compared to adjacent brainT2:hyperintense solid component compared to adjacent brain

02-Mar-1659

02-Mar-1660

MRI T1, MRI gadolinium images showing sellar pilocytic astrocytoma, (C) MRI T1, (D) MRI gadolinium images showing cerebellar pilocytic astrocytoma02-Mar-1661

Pilocytic astrocytoma- TREATMENTSurgical resection of cerebellar pilocytic astrocytomas is considered the treatment of choiceResection of mural nodule key surgical objectiveResection of cyst wall controversial ??Radiation therapy is strictly avoided, given its risk of causing significant morbidity in children younger than 5 years of ageLong-term prognosis is dependent on the extent of resection,presence of brain stem invasion and histological features of malignancy02-Mar-1662

Brain stem gliomas (BSG) include glioma occuring in the midbrain, pons and medulla.75 % occur in children25% in adults.Median age of presentation in childhood is 6.5 years (75% occur in pts younger than 20 years of agepeak incidence between age of 5 to 10 years)No sex predilectionKaplan AM, Albright AL, Zimmerman RA, Rorke LB, Li H, Boyett JM, et al. Brainstem gliomas in children. A Children's Cancer Group review of 119 cases. Pediatric neurosurgery 24:185-192,1996

Brainstem gliomas (BSG)02-Mar-1663

02-Mar-1664

HALLMARKS OF BSGBilateral long tract signsBilateral multiple contiguous cranial nerve palsiesHorners syndromeInter Nuclear OphthalmoplegiaFocal tumors tend to have a slow progression to neurologic signs in contrast to diffuse malignant tumors, which have a fast progression to neurologic signs.02-Mar-1665

BSGClassificationThe most recent classification system by Choux et al based on both CT and MRI imaging

Type I DiffuseType II Intrinsic, focalType III Exophytic, focalType IV Cervicomedullary

Pediatric Neurosurgery. New York, Churchill Livingstone, 2000, pp 471491.02-Mar-1666

BSGType I : Diffuse brainstem gliomas 75% of all BSG Hypointense on CT No significant enhancement on MRI.Characterized by diffuse infiltration and swelling of the brainstem. Typically, are malignant fibrillary astrocytomas (WHO grade III or IV).

02-Mar-1667

BSGType II : Focal intrinsic tumors ( cystic/solid )Sharply demarcated from surrounding tissue on MRI and are associated with less brainstem edema. Majority of these lesions are low grade gliomas (WHO I or II). Contrast enhancement : variable Type III : Exophytic tumors that arise from the subependymal glial tissue of the fourth ventricle and mostly grow dorsally or laterally.MRI characteristics similar to type II lesions,and histologically, these lesions are usually low-grade lesions (WHO I or II) like type II lesions.

02-Mar-1668

BSGType IV lesions are cervicomedullary brainstem gliomas.Imaging, histology and behavior : similar to intramedullary spinal cord gliomas.Majority are low-grade, non-infiltrative tumors.02-Mar-1669

Diffrence between paediatric and adult BSGIn children,

commonest were pyramidal weakness (83.1%), palatal palsy (69.2%), gait ataxia (47.9%), facial palsy (80.3%), cerebellar signs (76.1%).Raised ICP and papilledema seen 20%Rapid onsetMost frequent site in both adults and children is ponsDiffuse pontine glioma long term survival of < 1 year.

In adultsFacial palsy (86.7%) and pyramidal weakness (83.3%) palatal palsy (80%) and cerebellar signs (76.7%).Raised ICP and papilledema seen 40%.Slower in adults. Preferece to pons is less striking.Diffuse pontine glioma of adults is more often grade-2 lesion and is far more radiosensitive , associated with a long term survival of 7.3 years

02-Mar-1670

Brainstem Tumors: Medullary

15 years old male. JPA confirmed

02-Mar-1671

Brainstem Tumors: Pontine

9 years old male. Glioma grade II WHO02-Mar-1672

Brainstem Tumors: Mesencephalic

19 years old female. JPA02-Mar-1673

Brainstem: Quadrigeminal plate

16 years old female

02-Mar-1674

BSG..ManagementBiopsy : only for indeterminate lesionsStereotactic biopsy: can provide diagnostic tissue. Stereotactic radiosurgeryNot without risk:Damage to the cranial nerves and long tracts Tissue heterogeneity Focal brain stem tumors are considered amenable to surgical resection, which is often the primary treatment of choice. Dorsal midbrain tumors, such as tectal gliomas known to be indolent and stable clinically and radiographically for many years, may be observed02-Mar-1675

02-Mar-1676

BSG..Management

Choroid Plexus TumorsNeoplasms of the choroid plexus.Lateral ventricles : most common location in children. 4th ventricle : most common location in adults.4-6% of the intracranial neoplasms in children younger than 2 years.Choroid plexus tumorsChoroid plexus papilloma (WHO Grade 1)Atypical choroid plexus papilloma (WHO Grade 2)Choroid plexus carcinoma (WHO Grade 3)02-Mar-1677

Choroid Plexus TUMORS..ClinicalHydrocephalus and raised ICTThe tumor itself can cause mass effect.Surgery may not resolve HCP (derangement of reabsorption mechanisms or blockage at other sites in the ventricular system) Treatment of hydrocephalus must be considered both before and after any surgical procedures. An acute increase in ICP : V P Shunt. Hydrocephalus often resolves following removal of the mass.

02-Mar-1678

Choroid Plexus PapillomaManagementTotal surgical resection is the goal.Complete removal: generally curative in papilloma Choroid plexus carcinoma -total resection leads to the best possible outcome.Adjuvant CT and RT have been demonstrated to increase survival02-Mar-1679

Dermoid cystCongenital ectodermal inclusion cysts.Extremely rare < 0.5% of primary intracranial tumors Midline sellar, parasellar, or frontonasal regions : most common sites.Posterior fossa ( vermis or within the 4th ventricle)Growth can lead to rupture of the cyst contents, causing a chemical meningitis that may lead to vasospasm, infarction, and even death02-Mar-1680

Dermoid cystWell-defined, lobulated, pearly mass of variable size.Characteristically - cyst contains thick, disagreeable, foul smelling, yellow material due to the secretion of sebaceous glands and desquamated epithelium The cysts may also contain hair and/or teeth02-Mar-1681

Atypical rhabdoid teratoid tumorYounger age than PNET Median age at diagnosis less than 2 years of ageLack of response to standard therapySpecial microscopic techniquesRhabdoid cells: small round cells (only a minority of the tumor)Cerebellum most common siteMay spread through the subarachnoid spaceImaging similar to medulloblastoma, calcification is common, necrosis, cysts and hemorrhage

02-Mar-1682

02-Mar-1683

TreatmentTumor TypeSurgeryXRTChemoMedulloblastoma +++ CrSp +++Low grade astro +++focal ---- cerebellar +++???? ----High grade astro/GBM +++ +++ ?Brain stem glioma (exophytic)focal ?Ependymoma +++focal ----02-Mar-1684

TREATMENT OF ASSOCIATED HYDROCEPHALUS

Some advocate Initial placement of VP shunt or EVD prior to definitive surgery (waiting 2 wks before surgery) because of possibly lower operative mortality. Theoretical risks of using this approach include the following:1. Placing a shunt is generally a lifelong commitment, whereas not all patients with hydrocephalus from a p-fossa tumor will require a shunt2. Possible seeding of the peritoneum with malignant tumor cells e.g. with medulloblastoma.3. Some shunts may become infected prior to the definitive surgery4. Definitive treatment is delayed, and the total number of hospital days may be increased5. Upward transtentorial herniation may occur if there is excessively rapid CSF drainageAccordingly, Most centers are using a combination of corticosteroids, early surgery, and external ventricular drainage rather than VP shunting02-Mar-1685

ETV- role in m/mETV, prior to posterior fossa surgery, reduces the incidence of hydrocephalus because preoperative normalization of CSF hydrodynamics decreases the risk of permanent postoperative impairment of the CSF circulation.However, the routine application of preoperative ETV is not indicated because of the small number of patients requiring definitive treatment for hydrocephalus.ETV may be used for persistent or progressive hydrocephalus following tumor removal.02-Mar-1686

CONCLUSION

Pilocytic astrocytoma bears the best outcome.Management of hydrocephalus still remains controversial.Though surgery and RT remains the treatment of choice for medulloblastoma; optimal craniospinal radiation dose remains debatable.Outcome for brainstem gliomas remains dismal.

02-Mar-1687

Thank You02-Mar-1688

intra axial posterior fossa tumor

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