Brain tumours Flashcards
Definition of Brain tumors
Brain tumors refer to abnormal growths of cells within the brain.
These tumors can be benign (non-cancerous) or malignant (cancerous).
They can originate from the brain itself (primary tumors)(most common in children) or spread from other parts of the body (secondary or metastatic tumors)(most common in adults)
Types of of Brain tumors
1) Gliomas: These tumors arise from the glial cells, which support and nourish the neurons in the brain. They include:
a. Astrocytomas: Originate from astrocytes and can be low-grade (benign) or high-grade (malignant) tumors.(MOST COMMON TUMORS IN CHILDREN AND ADULTS!) (Tends to arise from cerebellar hemisphere or along the optic nerve)
b. Oligodendrogliomas: Arise from oligodendrocytes and can be slow-growing, often occurring in young adults.
c. Ependymomas: Develop in the cells lining the fluid-filled spaces within the brain (ventricles).
2) Meningiomas (F>M): Arise from the meninges (from arachnoid cells) parasagitally( paraller to sagittal bone)
They are typically benign, slowly growing, homogenous enchancing.
Attach to dura matter leading to hyperostosis
3) Choroid Plexus Papilloma= Rare, benign tumours arising from the cerebral ventricles leading to hydrocephalus (due to high CSF production).
4)Pituitary Adenomas: These tumors develop in the pituitary gland and can affect hormone regulation.
5) Medulloblastomas: Primarily found in children, these tumors develop in the cerebellar vermis and can spread through CSF=drop metastasis (A tumor originating from posterior fossa spreads down to spinal cord)
6) Ependyomas : In children= 4th ventricle, In adults = spinal cord. Drop metastasis. Spinal MRI is indicated.
7)Vestibular schwannoma or Acoustic neuroma: Originating CN VIII, appear as homogenous-enchancing masses at cerebellopontine angle)
8) Craniopharyngiomas: These tumors form above the sella turcica. Appear as
single or multiple calcified cysts.
Metastatic tumours: Follow cerebral flow, appear as contrast enchancing lesions along the gray-white matter junction.
Causes of Brain tumors
Radiation Exposure: Previous radiation treatment to the head or neck.T
Genetic syndromes:
i) Neurofibromatosis 1= Associated with optic n gliomas and schwannomas
ii)Neurofibromatosis 2= Bilateral scwannomas
iii) Tuberous sclerosis= Subependymal giant cell astocytoma
iv) Turcot syndrome= Risk of colonic polyps, gliomas, medulloblastomas.
v) Von-Hippel-Lindeu= Cerebellar and retinal hemangioblastomas
Family History: Inherited genetic syndromes, such as neurofibromatosis, can predispose individuals to brain tumors.
Immune System Disorders: Conditions that weaken the immune system, such as HIV/AIDS, may increase the risk.
Age: Some types of brain tumors are more common in specific age groups, such as medulloblastomas in children.
Symptoms of Brain tumors
Headaches: Often more severe in the morning or with changes in position( due to high ICP), dull , slowly progressive ,poorly localized.
Focal neurological deficits: Seizures: Sudden/unexplained/focal or generalized, Cranial Nerve palsies.
Neurocognitive and Behavioral Changes: Memory problems, personality changes, or difficulty concentrating.
Primary motor cortex: Weakness, numbness, or problems with coordination.
Primary sensory cortex: Astereognosis
Broca’s areas= Expressive aphasia
Wernicke’s areas= Receptive aphasia
Vision or Hearing Problems: Blurred vision, double vision, or hearing loss.
Psychiatric symptoms= Depression.
Pituitary tumours= Bitemporal hemianopsia( due to compression of optic chiasm)
Vestibular Schwannoma= Hearing loss and tinitus ( due to compression of 8th C.N)
Craniopharyngeoma= Growth and developmental disturbance ( due to compression of pirtuitary gland)
Meningiomas= Seizures
Germinomas/Pinealomas= Parinaud’s syndrome : Paralysis of upward gaze, pupillary light-near dissociation, convergence-refraction nystagmus)
Infratentorial tumours: Interrupt CSF flow leading to occlusive hydrocephalus
( microcephaly in infants) C. N palsies or cerebellar symptoms( ataxia).
Diagnosis of Brain tumors
Brain MRI with contrast( good for soft tissue structures+ shows edema around tumour)
CT (Good for calcifications)
Non contrast CT is done first if there is suspiscion of intracranial haemorrhage, followed by brain MRI(after 7-10 days)
Stereotactic biopsy for histopathological analysis and identification of unique molecular markers (e.g isocitrate DEH in gliomas/ WNT-activating mutation in medulloblastoma) that aid in treatment planning.
Treatment of Brain tumors
Combination of :
Surgery+ Preop embolization (shrink high vascularized tumours and make surgical resection easier)
Radiotherapy
Chemotherapy( intrathecally)(into CSF by lumbar puncture) :
Used in contrast enhanced lesions because this is the sign that BBB is destroyes, thus drug can enter it and reach the tumor.
Use of lipophilic chemo agents ( able to cross membrane) = Nitrosoureas, Carmustine, Lomustine
Symptomatic therapy:
Systemic glucocorticoids (Dexamethasone) to decrease cerebral edema
Anti-seizure medications: Levetiracetam (In case of seizuere, NOT prophylactically)
CSF shunts in case of hydrocephalus( Ventriculopleural, ventriculoatrial, ventriculoperitoneal)
