Pediatric Neurosurgical Neuropathology

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Pediatric Neurosurgical Neuropathology

• Brain tumors are second only to leukemias in
  children
• Brain tumors are the most common solid organ
  tumor in children
• 70 of pediatric brain tumors are in the
  posterior fossa
• Pilocytic astrocytoma
• Medulloblastoma
• Ependymoma

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CNS tumors pediatric vs. adult

• Adults 70 of tumors are supratentorial
• meningioma
• pituitary adenoma
• High grade astrocytoma
• Anaplastic astrocytoma (grade III)
• Glioblastoma multiforme (grade IV astrocytoma)
• Pediatric 70 in posterior fossa
• pilocytic astrocytoma (cerebellar astrocytoma)
• medulloblastoma

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Brain tumors intro

• Intracranial neoplasms
• Primary
• Secondary
• Metastatic
• Local invasion
• Tumors of the spinal cord

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Primary brain tumors intro

• Primary brain tumors are rare
• 2.5 of all cancer deaths
• Second most common type of tumor in children
• There are over 100 different brain tumors
• Most common types
• Astrocytomas
• Grades I-IV
• Medulloblastomas
• primitive neuroectodermal tumor-PNET
• Meningiomas
• Pituitary adenomas

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Clinical presentation

• Clinical symptoms depend upon
• Age, location, and type of tumor and grade
• Symptoms may include
• Increased intracranial pressure
• secondary to obstruction of CSF at aqueduct
• hydrocephalus (infants), headache, papilledema,
  vomiting
• seizures
• focal neurological deficits
• hormonal changes (pituitary adenoma)
• visual changes (diplopia, field defects)
• Pituitary adenoma - pressure on optic chiasm

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CNS tumors diagnosis

• Symptoms prompt neuroimaging
• CT and MRI
• intra-axial vs. extra-axial
• Location of tumor
• contrast enhancement
• typical of high grade
• also in some low grade, i.e., pilocytic
  astrocytomas

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CNS tumors location

• Extra-axial
• meningiomas
• Cerebral hemispheres
• grade II-III astrocytomas, GBM
• Crossing corpus callosum - GBM
• optic nerve - pilocytic astrocytoma (NF-1)
• Sella - Pituitary adenoma
• Peri-III ventricle - Pilocytic astrocytoma, GBM

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CNS tumors location

• posterior fossa (in children)
• pilocytic astrocytoma
• medulloblastoma
• brainstem (pons)
• pontine glioma (astrocytoma)
• spinal cord
• low-grade astrocytomas (grade I and II)

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Pilocytic astrocytomas

• Most common in children
• Grade I astrocytoma
• Cerebellum (posterior fossa), optic nerve
• Thalamic, spinal cord, cerebral
• Discrete, well circumscribed mass
• Often with associated cystic area
• Contrast enhancing
• Histologic appearance
• Biphasic piloid cells and microcystic areas
• Rosenthal fibers
• no mitoses

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Pilocytic astrocytomas

• Tumor of cerebellum, often with cyst, biphasic,
  Rosenthal fibers, piloid cells

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Astrocytoma - high grade

• Astrocytoma grade II and III are very, very rare
  in the pediatric population
• Grade IV - glioblastoma multiforme
• Diffusely infiltrating glial tumor of cerebral
  hemispheres
• Contrast enhancing tumor
• Histological appearance
• Densely cellular, with marked nuclear
  pleomorphism
• Numerous mitoses
• Endothelial proliferation
• Necrosis with pseudopallisading

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Glioblastoma (grade IV)

• Less common in children than adults, typical
  pathology (necrosis with psuedopallisading)

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Pontine glioma

• Diffuse expansion of pons, usually high grade
  astrocytoma (III-IV)

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Medulloblastomas

• PNET of posterior fossa in children
• Histologic appearance
• Densely cellular small blue cell tumor
• Numerous mitoses
• Apoptotic (karyorrhectic) cells
• Endothelial proliferation
• Necrosis
• neuronal or glial differentiation
• Homer Wright rosettes
• GFAP positive cells

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Medulloblastoma

• Mass arising in roof of fourth ventricle
• Homer Wright rosettes

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Ependymoma

• Mass arising in floor of fourth ventricle
• Perivascular pseudorosettes

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Meningiomas

• Discrete non-invasive tumor
• Extra-axial, pushes into brain
• Attached to dura
• Hyperostosis or invasion of skull common
• Histologic appearance
• Fibroblastic or menigothelial cells
• Meningothelial whorls
• Psammoma bodies
• Rare in children, may be intraventricular
  (lateral ventricles)

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Meningiomas

• Extra-axial tumor, meningothelial cells, whorls
  and psammoma bodies

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Ganglioglioma

• Cerebrum, cervicomedullary, often with cystic
  component
• Increased numbers of neurons (some binucleate)
  and increased glial cells (usually astrocytic)

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Craniopharyngioma

• Heterogeneous, cystic mass in suprasellar region
• Basiloid layer, stellate reticulum, wet
  keratin, often calcified

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Choroid plexus papilloma

• Lateral ventricle in children (fourth ventricle
  in adults)

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Germ cell tumors
Germinoma
Teratoma

• Pineal - 99 males, most are germinomas
• Suprasellar - often mixed germ cell tumor, 50
  female
• Tertomas are rare

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Metastatic tumors

• The most common brain tumor in adults is
  metastatic
• Metastatic tumors are rare in children
• The most common metastatic tumor in children is
  osteosarcoma
• Local extension of malignant tumors of vertebral
  bodies (Ewings sarcoma) or paravertebral soft
  tissues (neuroblastoma) are not uncommon

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Other tumors

• Subependymal giant cell astrocytoma (SEGA)
• Intraventricular tumor in Tuberous sclerosis
• Desmoplastic infantile ganglioglioma (DIG)
• Superficial cerebral tumor in infants
• Dysembryoplastic neuroepithelial tumor (DNET)
• Hamartomatous lesion associated with seizures
• Atypical teratoid rhabdoid tumor (ATR, AT/RT)
• Infants, posterior fossa, very malignant
• Eosinophilic granuloma
• A type of Langerhans cell histiocytosis
• Single discrete osteolytic lesion in skull
• Meningioangiomatosis
• Hamartomatous superficial cerebral lesion
  associated with seizures

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Hereditary syndromes

• Neurofibromatosis type I
• Café-au-lait spots
• Dermatofibromas, multiple
• optic nerve gliomas, bilateral
• plexiform neurofibroma
• Malignant peripheral nerve sheath tumor
• Neurofibromatosis type II
• bilateral acoustic neuroma
• multiple meningiomas
• ependymomas