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Neuro 2 > Pediatric Brain Tumors > Flashcards

Pediatric Brain Tumors Flashcards

1
Q

Brain Tumors in Children: Epidemiology

A
  • most common pediatric solid tumor accounting for 18-20% of all childhood cancers
  • 2nd most common malignancy after leukemia
  • most common in 1st decade of life
  • 2,200 cases/year or 3.3 cases per 100,000
  • survival to adulthood is 65%
  • 2 peaks early childhood + late adulthood (8th decade)
  • infratentorial tumors most common in children except in 1st year of life
  • male predominance in 1st decade
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2
Q

Brain Tumors Children Histology

A
  • embryonal histology is seen more commonly in 1st decade than in adults
  • Medulloblastomas, supratentorial primitive neuroectodermal tumors (PNET) & pineoblastomas occur almost exclusively in children & young adults
  • High grade gliomas (glioblastoma multiforme) are rare in the pediatric age group
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3
Q

Most common CNS tumors in Pediatrics?

A

-Astrocytomas

then PNETs, other gliomas, then ependymomas

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4
Q

Site of Pediatric Brain Tumors

A
  • Supratentorial 30-50%
  • Midline 10-15%
  • Infratentorial 50-60%
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5
Q

Brain Tumor Distribution & Age

A

11 yrs Infratentorial (supratentorial) Gliomas, PNET/Medulloblastoma, Germ cell

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6
Q

Pre-disposing factors for Brain Tumors

A
  • Ionizing Radiation
  • Other tumors (Kidney, Retinoblastoma)
  • Immune Suppression (Wiskott-Aldrich Syndrome, Ataxia-Telangiectasia, Acquired Immunodeficiency)
  • Familial Conditions
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7
Q

Origins of Pediatric Brain Tumors

A
  • Most arise from the supporting cells of the brain (glia) and are called “gliomas”
  • Others arise from the primitive nerve cells, that are much more common in children than in adults
  • A 3rd type of childhood brain tumor arises in the non-neuronal embryonal cells
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8
Q

WHO Classification of Glial Tumors

A
  • Astocytomas
  • Oligodendrogliomas
  • Ependymal Tumors
  • Choroid Plexus Tumors
  • Mixed Gliomas
  • GBM
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9
Q

WHO Classification of Neuronal Tumors

A
  • Gangliocytoma

- Anaplastic ganglioma

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10
Q

WHO Classification of Primitive Neuro Ectodermal

A
  • PNET
  • PNET with differentiation
  • Medulloepithelioma
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11
Q

WHO Classification of Pineal Cell Tumors

A
  • Pineocytoma

- Pineoblastoma

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12
Q

Clinical Presentation of Brain Tumor

A
  • Varied

- Location rather than histology

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13
Q

Clinical Manifestations of Pediatric Brain Tumors: Supratentorial

A

-Localizing Findings: seizures, Hemiparesis

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14
Q

Clinical Manifestations of Pediatric Brain Tumors: Midline (Hypothalamic/Optic, Craniopharynioma, Pineal)

A
  • Endocrinopathies: (Diabetes insipidus, Growth disorders, Dec. vision, Visual field deficits)
  • Signs of inc. ICP
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15
Q

Clinical Manifestations of Pediatric Brain Tumors: Infratentorial

A

-Signs & Symptoms related to inc. intracranial pressure

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16
Q

Clinical Manifestations of Pediatric Brain Tumors: Brain Stem

A
  • Cranial Nerve Deficit: (double vision, slurred speech, swallowing disorders, “crossed-weakness”)
  • Occasional Hydrocephalus
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17
Q

Hydrocephalus

A
  • associated with 80% of midline brain tumors
  • due to obstruction in ventricular system
  • Initial symptoms are early morning intermittent headaches & nausea/vomiting
  • most resolve after mass resection, but 15% require placement of shunt or ventriculostomy
  • complications include shunt failure, infection or hemmorhage
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18
Q

Ocular Pathology of Tumors

A

-Proptosis or ptosis

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19
Q

Papilledema

A

-blurring of optic disc margin with increased ICP

20
Q

Signs & Symptoms of ICP

A

Triad: AM headaches, Nausea/Vomiting, Lethargy

  • bulging fontanelle, sundowning of eyes, CN 6 palsy, HA/N/V
  • 1/3 post. fossa tumor patients will require permanent VP shunts following surgical debulking
  • presentation before diagnosis is 4-6 months
21
Q

Tumor Diagnostic Evaluation

A
  • H&P (neuro exam)
  • Diagnostic Imaging (CT, MRI, MRA, MRS)
  • Tissue Diagnosis (surgical biopsy, surgical resection, CSF cytology)
  • Metastatic evaluation (CSF evaluation, bone scan, bone marrow aspirates)
22
Q

MRI

A
  • preferred diagnostic study
  • easy manipulation of image plane
  • avoidance of ionizing radiation
  • sensitive to acute, subacute, & chronic blood products
  • expensive
  • lengthy exam often requiring sedation or anesthesia
23
Q

CT

A
  • fast
  • useful in emergent situations
  • less expensive
24
Q

Low Grade Astrocytoma

A
  • most common childhood brain tumor
  • 40% of all CNS tumors
  • may be supra or infratentorial
  • derived from astrocytes, which are major supportive cells
  • astrocytes constitute 40% of CNS cell population & are widely spread throughout the CNS including the optic nerves
25
Q

Astrocytoma: Grading

A
  • low grade are I & II which are histologically benign
  • grade III (anaplastic astrocytoma) & IV are malignant (glioblastoma multiforme)
  • high grade gliomas represent 7-11% of all CNS tumors
26
Q

Low Grade Astrocytoma Treatment

A
  • primarily a surgical disease
  • greater than 75% 5 year survival if gross total resection achieved (90% 5 yr survival and >70% 20 year survival
  • chemo/radiation options in those with residual tumor or recurrent disease
27
Q

Juvenile Pilocytic Astrocytoma

A
  • can be in optic pathway
  • can be seen with solid & cystic components
  • contrast enhancing tumor
  • elongated hair-like projections from neoplastic cells
  • presence of eosinophillic Rosenthal fibers & hyalinization of blood vessels
28
Q

Juvenile Pilocytic Astrocytoma

A
  • driven by an oncogenic process activating the MAPK pathway
  • KRAS activation, BRAF activation with either duplication of c’s 7 or v600E mutation causes activation of BRAF
  • patients with NF1 have loss of inhibitory gene NF1 causing KRAS activation
29
Q

Pilocytic Astrocytoma Mutations

A
  • BRAF fusion - in cerebellar tumors
  • BRAF V600E mutation - extracerebellar regions
  • NF1 loss - in optic pathway tumors
30
Q

Medulloblastoma

A
  • 20% of all CNS tumors (40% of posterior fossa tumors)
  • more common in children than adults
  • arise in primitive nerve cells
  • cerebrum location (primitive neuroectodermal tumor PNET))
  • cerebellar location: medulloblastoma
  • peak age is 3-4 years
  • male to female 1.5:1
31
Q

Medulloblastoma: Prognostic Factors

A
  • age
  • histology
  • size at diagnosis
  • metastatic spread
  • extent of resection
  • neurotrophin-3 receptor, TrkC, ErbB2, ErbB-4, C-myc overexpression
32
Q

Medulloblastoma: Treatment

A
  • malignant WHO grade IV grow rapidly & tend to spread through the CSF
  • often infiltrate adjacent brain structures preventing total resection
  • surgery with craniospinal radiation
  • Adjuvant chemotheraphy beneficial (especially in infants & in desseminated or recurrent disease)
33
Q

Medulloblastoma: Microscope

A
  • densely cellular, round, oval or angulated “carrot-shaped”
  • low vascular density, Homer-Wright rosette = pseudorosettes consisting of tumor cells surrounding a fibrillar area
  • hyperchromatic
34
Q

Medulloblastoma: Pathogenesis

A
  • Wnt pathway - good prognosis

- Shh (PTCH mutation) pathways - good in infants, intermediate in rest

35
Q

Brainstem Glioma

A
  • 15% of all CNS tumors
  • surgery contraindicated
  • uniformly fatal in 18-24 months & <10% 5 year survival
  • radiation therapy provides temporary improvement
  • supportive care
36
Q

Diffuse Intrinsic Pontine Glioma

A

-8-10% of all pediatric CNS tumors
-prognosis dismal, median survival from 9-11 months, only 20% past a year
~7 y/o
-symptoms: corticospinal long tract sighs (weakness or hemiparesis), ataxia, CN 6, 7, 8 defects (difficulty w/lateral gaze)
-diagnosis by MRI (engulfs basilar artery by tumor, diffuse extension into pons
-Treatment: not resectable, radiation helps prolong life

37
Q

Ependymoma

A
  • 9% of all CNS tumors
  • highest incidence in 1st 7 yrs of life, 1:1 M:F
  • arise from ependymal lining of ventricles or central canal of spinal cord
  • Posterior Fossa 60%
  • Spinal Cord 10%
38
Q

Ependymoma Microscope

A
  • Classic (WHO II) exhibits perivascular pseudorosettes of glial tumor cells that are radially arranged around the blood vessels
  • also true ependymal rosettes of tumor cells that form a central lumen on their own
39
Q

Ependymoma action

A
  • 50% of patients are <5yr at presentation
  • tumors are locally invasive
  • CNS dissemination is 7-10%
  • may be low grade or anaplastic
  • PNET variant is called ependymoblastoma
  • staging should include CSF examination & spinal MRI
40
Q

Ependymoma Prognostic Factors

A
  • surgical resection
  • brain stem involvement
  • age
  • stage at presentation
41
Q

Treatment of Brain Tumors

A
  • surgery
  • radiation
  • chemo
42
Q

Surgery

A
  • primary treatment modality
  • curative alone in only 20% of cases
  • goals - established histologic diagnosis reduction in tumor burden
  • extent of resection & outcome
  • notable exception: diffused brain stem gliomas
43
Q

Radiation Therapy

A
  • volume & dosage vary according to the histologic diagnosis
  • localized treatment unless high likelihood of neuraxis dissemination
  • medulloblastoma/PNET
  • age & radiation
44
Q

Radiation & the Developing Brain

A
  • development (axonal growth & synaptogenesis) is most rapid in first 3 years of life
  • rate of growth & development slows after age 6
  • maturation (degree of myelinization) isn’t complete until puberty
  • want to wait till after 3 but 7 is even better
  • effects delayed months to years after treatment
  • Neuropsychological effects: intellectual impairment, memory deficits, & inability to acquire new knowledge
  • Cognitive impairment is most pronounced in kids younger than 4-7
45
Q

Which is more common: infratentorial or supratentorial?

A

-infratentorial

Neuro 2 (16 decks)

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