Pediatric Neurosurgical NeuropathologyPediatric 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. adultCNS 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: introBrain tumors: intro

Intracranial neoplasms– Primary– Secondary

»Metastatic»Local invasion

Tumors of the spinal cord

Primary brain tumors: introPrimary 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 presentationClinical 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: diagnosisCNS 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: locationCNS 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: locationCNS tumors: location

posterior fossa (in children)– pilocytic astrocytoma– medulloblastoma

brainstem (pons)

– pontine glioma (astrocytoma) spinal cord

– low-grade astrocytomas (grade I and II)

Pilocytic astrocytomasPilocytic 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 astrocytomasPilocytic astrocytomas

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

Astrocytoma - high gradeAstrocytoma - 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)Glioblastoma (grade IV)

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

Pontine gliomaPontine glioma

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

MedulloblastomasMedulloblastomas 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

MedulloblastomaMedulloblastoma

Mass arising in roof of fourth ventricle

Homer Wright rosettes

EpendymomaEpendymoma

Mass arising in floor of fourth ventricle

Perivascular pseudorosettes

MeningiomasMeningiomas

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)

MeningiomasMeningiomas

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

GangliogliomaGanglioglioma

Cerebrum, cervicomedullary, often with cystic component

Increased numbers of neurons (some binucleate) and increased glial cells (usually astrocytic)

CraniopharyngiomaCraniopharyngioma

Heterogeneous, cystic mass in suprasellar region Basiloid layer, stellate reticulum, “wet” keratin,

often calcified

Choroid plexus papillomaChoroid plexus papilloma

Lateral ventricle in children (fourth ventricle in adults)

Germ cell tumorsGerm cell tumors

Pineal - 99% males, most are germinomas Suprasellar - often mixed germ cell tumor,

50% female Tertomas are rare

Germinoma Teratoma

Metastatic tumorsMetastatic 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 tumorsOther 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 syndromesHereditary 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