5. Neoplasms Flashcards
Types of CNS neoplasms
- Meningiomas
- Gliomas
- Astrocytoma
- Oligodendroma
- Ependymoma - Tumours of neurons
- Central neurocytoma
- Neuroblastoma (primitive neuroectodermal tumour)
- Medulloblastoma - Primary CNS lymphomas
- Sellar tumours
- Pituitary adenoma
- Craniopharyngioma - Pineal tumours
- Pineocytoma
- Pineoblastoma
- Germ cell tumours of CNS - Peripheral nerve sheath tumours
- Schwannoma (e.g Acoustic neuroma)
- Neurofibroma
- Malignant peripheral nerve sheath tumours
Neoplasms differentials by age
- Children
- Primary tumours > secondary tumours (3:1) - Adults
- Secondary tumours > primary tumours
Differentials by clinical history
- Known primary malignancy outside CNS
- Consider secondary metastatic cancer to CNS
- Usually multiple mets, but not always - Immunosuppression (HIV, chemotherapy)
- Consider CNS lymphoma or CNS infection mimicking tumour - Familial syndromes
- Neurofibromatosis-1
- Neurofibromatosis-2
- Tuberous sclerosis
- Von Hippel-Lindau syndrome
Differentials by sites
- Meninges
- Meningioma - Intra-/periventricular
- Ependymoma#
- Choroid plexus tumour#
- Neurocytoma (specifically 3rd ventricle) - Midline/sellar region
- Pituitary adenoma
- Cranipharyngioma#
- Germ cell tumours# - Supratentorial
- Neuroblastoma#
- CNS lymphoma
- Gliomas (pilocytic astrocytoma#, glioblastoma multiforme, oligodendroma) - Infratentorial
- Medulloblastoma#
- Gliomas (pilocytic astrocytoma#, glioblastoma multiforme, oligodendroma)
= tumours seen in children
Features of meningioma
- Originates from meningothelial cells (cerebral convexities, falx cerebri)
- Location: adherent to meninges
- WHO grade I-III (type I most common)
- Common & slow-growing, may invade skull bone
- Females > males
Molecular pathogenesis of meningioma
Loss of 22q (NF-2 gene) - hence seen as one of the
tumours in neurofibromatosis-2
Morphology of meningioma
- Grossly: tumour stuck onto meninges
2. Histologically: psammoma bodies
Types of Gilomas
- Astrocytoma
- Oligodendroma
- Ependymoma
Features of astrocytoma
- Originates from astrocytes
- Location: supra-/infratentorial
- WHO grade I-IV
- Grade I: Pilocytic astrocytoma (seen in children)
- Grade IV: Glioblastoma multiforme (seen in middle-
aged & elderly, very bad prognosis)
Morphology of astrocytoma
- [Pilocytic astrocytoma] may have cystic component
- [Glioblastoma multiforme] ‘butterfly tumour’, very aggressive, crosses midline, palisading necrosis, nuclear pleomorphism
Features of oligodendroma
- Originates from oligodendrocytes (constitutes 5-25% of all gliomas)
- Location: cerebral cortex
- WHO grade I-III
- Headaches & seizures
- Responds to chemotherapy
Molecular pathogenesis of oligodendroma
- Oligodendrocytes → Oligodendroma WHO grade I:
LOH 1p, LOH19q, LOH 4q - Oligodendroma
- WHO grade I → Anaplastic oligodendroma WHO grade III: CDKN2A deletion, CDKN2C mutation/deletion, LOH 9p & 10q
Morphology of oligodendroma
Histologically: fried-egg appearance
Features of epdenymoma
- Originates from ependymal cells lining ventricular system
- Location: intra-/periventricular
- Can cause hydrocephalus
- Seen in children
Molecular Pathogenesis of ependymoma
Some relation to neurofibromatosis-2
Morphology of ependymoma
Histologically: rosettes
Related tumour to ependymoma
Choroid plexus tumour
Choroid plexus tumour
- Papilloma (in children) or carcinoma
2. Can cause hydrocephalus
Classification of Tumours of Neurons
- Mature: central neurocytomas
2. Immature: neuroblastoma, medulloblastoma
Features of central neurocytoma
- Originates from neurons
- Location: near 3rd ventricle
- Can cause raised intracranial pressure
- Relatively good prognosis
- Seen in adults
Features of neuroblastoma (primitive neuroectodermal tumour)
- Originates from neurons, supratentorial counterpart of medulloblastoma
- Location: supratentorial
- Bad prognosis
- Seen in children
Molecular Pathogenesis of neuroblastoma
Differs from that of medulloblastoma even though it
is said to be the supratentorial counterpart of medulloblastoma
Features of medulloblastoma
- Originates from neurons, infratentorial counterpart of neuroblastoma
- Location: infratentorial (cerebellum, brainstem)
- Aggressive, spreads via CSF
- Treatment: surgery & radiotherapy
- Seen in children (accounts for 20% of brain tumours
in children)
Molecular pathogenesis of medulloblastoma
- Loss of 17p
- Alterations in Sonic hedgehog/patched pathway
- Alterations in Wnt signaling pathway
Morphology of medulloblastoma
Histologically: may form rosettes (but looks different
from those in ependymomas)
Features of primary CNS lymphoma
- Mostly non-Hodgkin B-cell lymphomas
- Location: supratentorial (multiple lesions)
- Associations: immunosuppression (HIV), EBV
Types of sellar tumours
- Pituitary adenoma
2. Craniopharyngioma
Features of pituitary adenoma
- Originates from pituitary gland
- Location: midline/sellar region
- May result in optic chiasma compression (bitemporal
hemianopia) & endocrine effects (overproduction of pituitary hormone, pressure atrophy of normal pituitary tissue)
Features of craniopharyngioma
- Originates from tooth-forming epithelium within the suprasellar region (embryonal remnant)
- Location: midline/sellar region
- May cause similar clinical manifestations as pituitary
adenoma - Good prognosis, but may recur
- Seen in children & adults (50-60 years old)
Morphology of craniopharyngioma
- Grossly: cystic, containing yellow viscous engine oil-like fluid
- Histologically: Cysts lined by stratified squamous
epithelium
Types of pineal tumours
- Pineocytoma
- Pineoblastoma (resembles neuroblastoma)
- Germ cell tumours of CNS
Features of germ cell tumours of CNS
- Takes several forms: teratomas (cystic, may be benign or malignant), germinomas, embryonal carcinomas, endodermal sinus tumours, choriocarcinomas
- Location: midline (pineal gland > suprasellar region)
- Males > females
- Seen more in children than adults
Types of peripheral nerve sheath tumours
- Schwannoma (e.g Acoustic neuroma)
- Neurofibroma
- Malignant peripheral nerve sheath tumours
Features of schwannoma
- Originates from Schwann cell
2. Location: cerebello-pontine angle
Features of malignant peripheral nerve sheath tumours
Seen in neurofibromatosis