Brain Neoplasms: General Considerations 1. Comprise: 10% of all tumors 2. Most common childhood neoplasms 3. Peak incidence at 5th decade 4. Supratentorial.

Brain Neoplasms:Brain Neoplasms:General ConsiderationsGeneral Considerations

1. Comprise: 10% of all tumors

2. Most common childhood neoplasms

3. Peak incidence at 5th decade

4. Supratentorial tumors in adults

5. Infratentorial tumors in childhood

Brain Neoplasms:Brain Neoplasms: General ConsiderationsGeneral Considerations

6. Different tumors in different ages 7. Primary tumors infiltrative, metastatic well-demarcated 8. Intraneural seeding occur, but no extraneural metastasis 9. Produce neurologic symptoms by size, location, invasiveness, and secondary effects

Varieties of brain tumorsVarieties of brain tumors

Meninges: meningioma, hemangiopericytoma Astrocytes: astrocytoma (various types) Oligodendrocytes: oligodendroglioma Ventricles: ependymoma, choroid plexus papilloma,

colloid cyst Vascular: hemangioblastoma Primitive cells: germinoma, medulloblastoma,

neuroblastoma, pineoblastoma, retinoblastoma Neuronal: ganglioglioma, gangliocytoma Pituitary: adenoma, craniopharyngioma Nerves: schwannoma, neuroblastoma

Incidence of Intracranial Incidence of Intracranial GliomasGliomas

(All ages)(All ages)

Glioblastomas

Astrocytomas

Ependymomas

Medulloblastomas

Oligodendrogliomas

Choroid plexus papillomas

Colloid cysts

55.0%

20.5%

6.0%

6.0%

5.0%

2.0%

2.0%

Incidence of Primary Incidence of Primary IntraspinalIntraspinal

Intramedullary GliomasIntramedullary Gliomas

Ependymomas

Astrocytomas (grades 1 and 2)

Glioblastomas (Astrocytomas grades 3 and 4)

Oligodendrogliomas

Other tumors

63.0%

24.5%

7.5%

3.0%

2.0%

Frequent brain tumorsFrequent brain tumors

Meningioma Astrocytoma/glioblastoma Oligodendroglioma Ependymoma Medulloblastoma Schwannoma/neurofibroma Phakomatosis

MeningiomaMeningioma

Arachnoid cells originAttached to dura, subduralCommon sitesChanges in cranium Hyperostosis Invasion

Microscopic: whorls and psammoma bodies

GliomasGliomas

Astrocytes- astrocytomas– Fibrillary– Pilocytic

Oligodendrocytes- oligodendrogliomas Ependyma- ependymomas

AstrocytomaAstrocytomass

Adults:

Childhood:

SupratentorialSolidMalignant

InfratentorialCysticBenign

Adult vs childhood astrocytomasAdult vs childhood astrocytomas

Adult: fibrillary. Grading varies from low grade malignancy to one of most malignant brain tumor.

Childhood: pilocytic. Very low grade tumor (benign).

Fibrillary astrocytomasFibrillary astrocytomas

Grossly solid Common in cerebral hemispheres Low grade in young, higher grade in older Grading

– astrocytoma (low grade)– Anaplastic astocytoma– glioblastoma multiforme

Fibrillary astrocytoma: microscopicFibrillary astrocytoma: microscopic

Low grade- hypercellularity, pleomorphism Anaplastic- as above plus mitosis, vascular

endothelial proliferation Glioblastoma multiforme- as above plus

necrosis and pseudopalisades. Grossly variegated appearance (multiforme)

Pilocytic astrocytomaPilocytic astrocytoma

Common in childhood Most slow growing of the gliomas Sites: cerebellum, around III V., optic nerve Grossly cystic with mural nodule Microscopic

– elongated hair-like (pilo) elongated cells– Rosenthal fibers

Rosenthal fiber definitionRosenthal fiber definition

Dense, eosinophilic fibers within cytoplasmic processes of astrocytes.

Correspond to aggregate accumulation of intermediate filaments in these processes.

OligoOligodendrdendroglioogliomamaSlow growing tumor

Potentially malignant

Calcifications

Tumors in Tumors in VentriclesVentricles

1. Ependyma: Ependymoma

2. Choroid Plexus: Papilloma

EpendymomasEpendymomas

Arise from ependymal lining- ventricles and central canal of spinal cord

Common in childhood 4th V. common in cerebrum Most common tumor of spinal cord

parenchyma in adult Microscopic

– perivascular pseudorosettes– ependymal rosettes

Primitive neuroectodermal tumorsPrimitive neuroectodermal tumors

Neuroblastoma- cerebral hemispheres Medulloblastoma- cerebellum Ependymoblastoma- ventricles Pineoblastoma- pineal region

MedulloblastomaMedulloblastoma

Origin: primitive neuroectodermal cells Age: 1st decade of life Site: vermis of cerebellum May cause hydrocephalus Subarachnoid dissemination

Histologic patterns: definitionsHistologic patterns: definitions

Whorls: onion-skinning pattern of tumor cells Psammoma bodies: laminated calcium Pseudopalisading: lining up of the tumor cells

around a central necrotic area Palisade: lining up of tumor cells around their

own cytoplasmic processes. No necrosis. Pseudorosette: tumor cells around blood

vessels, cells equidistant from vessel walls. Rosettes: tumor cells around central lumen or

fibrillary area of cellular processes

Brain Tumors: Brain Tumors: MicroscopicMicroscopic

Meningioma Whorls and psammoma bodiesGlioblastoma PseudopalisadesOligodendroglioma Mosaic/poached-eggEpendymoma Perivascular pseudorosettesMedulloblastoma Rosettes

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1. Schwannoma viii Cranial nerve (Acoustic sch.) Spinal roots, posterior Peripheral nerves

2. Neurofibroma Spinal Roots, rare Peripheral nerves

3. Malignant variants Rare

Peripheral nerve tumorsPeripheral nerve tumors

Schwannoma Schwann cells Compress the nerve trunk Encapsulated Easily resectable without

nerve damage Microscopic:

– Antony A and B fibers– Verocay bodies

Neurofibroma Schwann cells, neurites,

fibroblasts Fusiform and involves

nerve trunk Not encapsulated Not resectable without

sacrificing nerve Micro- Intermingled cells

with wavy nuclei

Metastatic brain tumorsMetastatic brain tumors

Most common brain tumor in adults. Common primary sites: melanoma, lung,

breast, GI tract, kidney. Most are in cerebrum (MCA territory). In gray-white junctions due to rich capillarity Discrete, globoid, sharply demarcated

tumors. Amenable to surgical resection. Single or multiple. Brain edema frequent.

Phakomatosis: definitionPhakomatosis: definition

Phakos (Greek): lentil mole or freckle. Neurologic abnormalities combined with

defects of skin or retina, explained by their common ectodermal origin.

Involvement of visceral organs

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((NNeeuurrooccuuttaanneeoouuss ddyyssppllaassiiaa))

1. Neurofibromatosis (von Recklinghausen's dis.)

2. Tuberous Sclerosis

3. Sturge-Weber disease (Encephalofacial Angiomatosis)

4. von Hippel-Lindau Disease

5. Neurocutaneous Melanosis

NeurofibromatosisNeurofibromatosis

1. Dominant inheritance

2. Multiple neurofibromas Central - CNS peripheral nerves

3. Increased incidence of: meningioma glioma schwannoma - bilateral VIII N.

4. Cafe-au-lait (melanosis) in skin

5. Elephantiasis: increased connective tissue

Tuberous SclerosisTuberous Sclerosis

1. Dominant inheritance

2. Clinical triad: seizures mental retardation adenoma sebaceum

3. Retinal hamartoma (phakoma)

4. Tubers in cerebral cortex

5. Subependymal giant cell astrocytoma

6. Hamartomas in other organs: heart, kidney

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