Pediatric Neurosurgical Neuropathology by sammyc2007

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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
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
Brain tumors: intro

   Intracranial neoplasms
    – Primary
    – Secondary
       » Metastatic
       » Local invasion
   Tumors of the spinal cord
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
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
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
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
CNS tumors: location

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




            Tumor of cerebellum, often with cyst,
              biphasic, Rosenthal fibers, piloid
              cells
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
Glioblastoma (grade IV)




   Less common in children than adults, typical
    pathology (necrosis with psuedopallisading)
Pontine glioma




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




   Mass arising in roof of
    fourth ventricle
   Homer Wright rosettes
    Ependymoma




   Mass arising in floor of
    fourth ventricle
   Perivascular
    pseudorosettes
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)
Meningiomas




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




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




   Heterogeneous, cystic mass in suprasellar region
   Basiloid layer, stellate reticulum, “wet” keratin, often
    calcified
Choroid plexus papilloma




   Lateral ventricle in children (fourth ventricle
    in adults)
 Germ cell tumors
Germinoma                       Teratoma




    Pineal - 99% males, most are germinomas
    Suprasellar - often mixed germ cell tumor, 50%
     female
    Tertomas are rare
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 (Ewing’s sarcoma) or paravertebral soft tissues
    (neuroblastoma) are not uncommon
      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
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

								
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