Brain Tumours of Childhood

Transkript

1 Brain Tumours of Childhood J.F.Schneider, MD Dpt. Pediatric Radiology University Children s Hospital, Basel

2 15% of tumors in children are CNS tumors They are second only to leukemia Three age ranges with different tumor differential diagnosis under 1 year of age between 4 and 15 years adults

3 Infratentorial tumors Supratentorial tumors Packer R, Pediatr Clin N Am, 2008

4 Infratentorial tumors differential diagnosis CHILDREN Cerebellar astrocytoma Medulloblastoma Brainstem glioma Ependymoma ADULTS Schwannoma Meningeoma Epidermoid Metastases

5 85% of cerebellar glioma in children are pilocytic astrocytoma Tumor Relative Incidence Presentation Diagnosis Prognosis Cerebellar Astrocytoma 35% to 40% 3 6 months of limb ataxia; Cerebellar hemisphere 65% to 85% survival; secondary headaches, cystic and solid dependent on stage/type; (mural nodule) components poorer (20% to 70%) in infants

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7 Association between JPC and Neurofibromatosis Type I NF-1 associated JPC show : obligatory loss of NF1-expression no mutation on p53 in Chr. 17p ( adult astrocytoma)

8 Optic pathways low-grade glioma in NF1 20% children with NF-1 develop visual pathways tumors visual loss, strabismus, proptosis, nystagmus Possible extension to hypothalamus and endocrinologic disturbances

9 Same patient, 2-years follow-up

10 Brain stem glioma Tumor Relative Incidence Presentation Diagnosis Prognosis Brain stem glioma 10% - 15% 1 4 months of double vision, unsteadiness, weakness, cranial nerve deficits facial weakness, swallowing Diffusely expanded, minimally or partially enhancing mass in 80%; 20% more focal tectal or cervicomedullary 90% of cases: 18-month mortality in diffuse tumors better in localized Tumors

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17 QUIZZ Pilocytic Astrocytoma

18 Medulloblastoma Tumor Relative Incidence Presentation Diagnosis Prognosis Medulloblastoma 35% to 40% 2 3 months of headaches, Heterogeneous or 65% to 85% survival; vomiting, ataxia homogeneously enhancing dependent on stage/type; fourth ventricular mass poorer (20% to 70%) may be disseminated in infants

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23 Older children have atypical medulloblastoma

24 Medulloblastoma is a paradigm of the embryonal tumor model Rapid proliferation of granule cell precursor (GCP) cells in the cerebellum leads to formation of the internal granular layer

25 Granular Cell Precursor cells migration Sonic Hedgehog concentration gradient, Cell-cycle exit and begin of differentiation High Shh concentration Low Shh concentration

26 High Shh concentration Low Shh concentration ventricular zone innermost layer classic medulloblastoma and stem cell markers

27 external germinal layer predominantly from the desmoplastic type Activation of Shh cascade High Shh concentration Low Shh concentration

28 Ependymoma Tumor Relative Incidence Presentation Diagnosis Prognosis Ependymoma 10% to 15% 2 5 months of unsteadiness, headaches, double vision, Usually enhancing, fourth ventricular mass with cerebellopontine and facial asymmetry predilection 75% survival in totally resected lesions

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32 Pediatric ependymoma adult ependymoma Monosomy 17 different chromosomal signature different signalling pathways Gains in Chr. 1q is associated with a poor clinical course

33 New insights Many ependymoma maintain the expression profiles of progenitor cells. Radial glial cells are multipotent progenitor cells for: neurons astrocytes oligodendrocytes ependymal cells

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35 Stem cell pool

36 Medulloblastoma Ependymoma Pontine glioma Pilocytic astrocytoma

37 Analysis of seven principle components: ADC and 6 metabolites (MRS)

38 Pituitary tumors of childhood

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41 QUIZZ Prolactin secreting adenoma

42 Clinical manifestations of craniopharyngiomas

43 Favourably localized tumors: complete resection Unfavourably localized tumors: best management is controverse surgery radiation Müller, Horm Res 2008

44 Conclusions Pediatric CNS tumors are genetically and biochemically different from their adult counterpart Better understanding from the stem cell concept Multivariate analysis including MRI, DWI and MRS is mandatory