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Description of glial cell tumours –Features : Children and young adult : § Commonest solid tumour (20%)§ Usually infra-tentorial§ Pilocytic Astrocytoma – most common§ Usually manifests early with increase in Intra-cranial pressure and prognosis is better than adult.Adults and elderly: § Astrocytomas are the commonest§ Glioblastoma Multiforme comprises 40%.§ Usually Supra-tentorial and presents late.Natural History : Pilocytic astrocytoma • More common in young & children• Usually presents as posterior fossa tumour• Slow growing tumor.• Tumor usually localized and well delineated.• Do not progress to higher grade.• H/P - ‘rosenthal fibre’ ++• P53 gene - not inactivated.Diffuse (oligodendrocytic) astrocytoma - • Occur at any age, but usually occur in young adult.• Arises from cerebral hemisphere.• Relatively slow growing• Subgrouped – a) fibrillary, b) protoplasmic c) gemistocytic.• These subgroups have prognostic implication. Gemistocytic variety is more aggressive.• May progress to higher grade with time.
Anaplastic astrocytoma - • Occur in middle age• Diffusely infiltrating astrocytic tumour.• Rapidly growing tumour. Produce symptoms early and rapidly progressive disease.• H/P- Diffuse endothelial proliferation. But no necrosis.• Progression to Glioblastoma occurs with time.Glioblastoma (grade –IV)- § Occur at any age. But more in elderly ( >60 yr)§ Poorly differentiated astrocytic tumor. Rapidly progressive fatal disease.§ Occur in cerebral hemisphere§ H/P- Necrosis always seen. Also microvascular proliferation seen. Multinucleated giant cell – hallmark of Glioblastoma.§ Profuse Peritumoral oedema seen.§ Cross corpus callosum some times involved; called ‘ butter-fly’ tumor. Natural history of Glioblastoma:• Pilocytic astrocytoma usually donot progress to higher grade.• Diffuse astrocytoma – progress to higher grade (usually after 10-15 yr)• Anaplastic astrocytoma – usually progress within 2-4 yr.• All form ‘secondary glioblastoma’Glioblastoma Two types – A) Primary Glioblastoma : arise de novo B) Secondary Glioblastoma: progression from low grade gliomas to secondary Glioblastoma occurs with time. Primary Glioblastoma: • Tumour is intra & inter heterogeneous• On examination macroscopically -§ Grey mass with hemorrhage§ False capsule usually seen. It is formed due to compression of normal brain tissue.• Spreads of malignant cells occur along white matter tract. Tumour cells migrate from gross disease into adjacent normal brain tissue. Peri-tumour edema is infiltrated with migratory cells. These migratory cells form secondary masses in adjacent brain tissue. Thus it appeared to be multi-focal (‘multiforme’) in origin. So earlier used to be called Glioblastoma multiforme.• But, now it is known to be a single tumor with spread to adjacent brain parenchyma; ‘brain to brain metastasis’. At present, the disease entity called ‘ Glioblastoma’.Subtype - 1. Giant cell glioblastoma 2. Gliosarcoma. These subtypes are more aggressive, response to treatment is poor and probably chemo-resistant. Secondary glioblastoma • Occur in younger population.• Arise from lower grade astrocytomas (diffuse or anaplastic).• Have some lower grade components along with high grade components ( mixed pathologic features)• H/P- Inflammatory infiltration seen in the tumour.• Secondary Glioblastoma is more chemo-sensitive and better prognosis than primary Glioblastoma.
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Brain Tumour Foundation Of India Tata Memorial Hospital,
Ernest Borges Marg, Parel, Mumbai - 400 012, INDIA
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