Brain Tumours Flashcards
What are brain tumours?
They are defined as a growth of cells within the brain that multiples in an abnormal, uncontrollable manner
What are the six main classifications of brain tumours?
Metastatic Brain Cancer
Gliomas
Meningiomas
Vestibular Schwannoma
Medulloblastomas
Craniopharyngioma
What is metastatic brain cancer?
It occurs when cancer cells spread from their original site to the brain
What is the most common form of brain tumour?
Metastatic brain cancer
What are the five primary tumour sites that most commonly spread to the brain?
Lung
Breast
Colorectal
Melanoma
Kidney
What is the most common primary tumour site that spreads to the brain?
Lung
What are gliomas?
They are defined as tumours that originate from the glial cells of the brain or spinal cord
What are the three subclassifications of gliomas?
Astrocytomas
Oligodendrogliomas
Ependymomas
What are astrocytomas?
They are defined as tumours that originate from astrocyte cells
What are the function of astrocytes?
They maintain the external environment of neurones by maintaining the correct ion concentration
What are the three subclassifications of astrocytomas?
Low Grade Astrocytoma
Pilocytic Astrocytoma
Glioblastoma Multiforme
What are low grade astrocytomas?
These are defined as benign tumours that develop from slow growing astrocytes
What are pilocytic astrocytomas?
These are defined as benign, paediatric tumours that develop from slow growing astrocytes
What investigation can be used to diagnose pilocytic astrocytomas?
Brain biopsy
How do pilocytic astrocytomas present on brain biopsies?
Rosenthal fibres (corkscrew eosinophilic bundle)
What are the most common primary brain tumours in children?
Pilocytic astrocytoma
What are glioblastoma multiformes?
These are defined as malignant tumours that develop from rapidly growing, atypical astrocyte
What are the most common primary tumour in adults?
Glioblastoma multiformes
What are the two investigations used to confirm the diagnosis of glioblastoma multiforme’s?
CT/MRI scans
Brain biopsy
What are the two features of glioblastoma multiforme’s on an MRI scan?
An irregular mass with central necrosis and a rim enhanced with contrast
Periventricular subependymal spread
How do glioblastoma multiforme’s present on brain biopsies?
They present as pleomorphic tumour cells with bordering necrotic areas
What are oligodendromas?
They are defined as tumours that originate from oligodendrocytes cells
What is the function of oligodendromas?
They function to form the myelin sheath around the neurone axons
Are oligodendromas benign or malignant?
Benign
Where are oligodendromas usually located?
Frontal lobes of the brain
What investigation is used to confirm the diagnosis of oligodendromas?
Brain biopsy
How do oligodendromas present on brain biopsies?
They present as calcifications with a ‘fried-egg’ appearance
What are ependymomas?
They are defined as tumours that originate from ependymal cells
What is the function of ependymal cells?
They line the ventricles of the brain and central canal of the spinal cord where CSF flows
Are ependymomas benign or malignant?
Benign
Where are ependymomas usually located?
4th ventricle of the brain
What clinical feature is associated with ependymomas? Why?
Hydrocephalus
These tumours can obstruct the flow of CSF
What investigation is used to confirm the diagnosis of ependymomas?
Brain biopsy
How do ependymomas present on brain biopsies?
Perivascular pseudorosettes
What are meningiomas?
They are defined as tumours that originate from meninge cells
What is the function of meninge cells?
They form the membranes that surround the brain and spinal cord
What do meningiomas specifically arise from?
The arachnoid cap cells of the meninges, which are typically located next to the dura mater
Are meningiomas benign or malignant?
Benign
Meningiomas are described as being extra-axial. What does this mean?
This means that these tumours are external to the brain parenchyma
What are the four locations in which meningiomas tend to be located?
Falx cerebri
Superior sagittal sinus
Convexity
Skull base
What two investigations can be used to confirm the diagnosis of meningiomas?
MRI/CT scan
Brain biopsy
How do meningiomas present on MRI/CT scans?
They present as well-circumscribed tumours, with a dural tail
What is a dura tail?
This is a connection between the tumour and dura mater
What are the features of meningiomas on brain biopsies?
Spindle cells in concentric whorls
Calcified psammoma bodies
What is the second most common primary brain tumour in adults?
Meningiomas
What is another term for vestibular schwannomas?
Acoustic neuromas
What are vestibular schwannomas?
They are defined as tumours that originate from Schwann cells surrounding the eighth cranial (auditory, vestibulocochlear) nerve
What is the function of Schwann cells?
They wrap around peripheral nerves to provide electrical insulation
Are vestibular schwannomas benign or malignant?
Benign
Where are vestibular schwannomas located? Why?
Cerebellopontine angle
This is due to the fact that the eighth cranial nerve is located between the pons and cerebellum
What are the four clinical features associated with vestibular schwannomas?
Unilateral Hearing Loss
Facial Nerve Palsy
Tinnitus
Imbalance
What genetic condition is associated with bilateral vestibular schwannoma?
Neurofibromatosis type II
What two investigations are used to confirm the diagnosis of vestibular schwannomas?
MRI/CT scan
Brain biopsy
How do vestibular schwannomas present on an MRI scan?
An enhancing mass in the cerebellopontine angle with extension into the internal acoustic meatus
What are the two features of vestibular schwannomas on a brain biopsy?
Antoni A/B patterns
Verocay bodies
What are verocay bodies?
They are defined as accelular areas surrounded by nuclear palisades
What are medulloblastomas?
They are defined as tumours that originate from the embryonic cells in the infratentorial compartment
What four structures are contained within the infratentorial compartment?
Midbrain
Pons
Medulla
Cerebellum
Are medulloblastomas benign or malignant?
Malignant
Where do medulloblastomas typically metastasise to?
CSF system
Which patient group tend to be affected by medulloblastomas?
Children
What investigation is used to confirm the diagnosis of medulloblastomas?
Brain biopsy
How do medulloblastomas present on brain biopsies?
Small, blue cells which appear in a rosette pattern
What are craniopharyngiomas?
They are defined as tumours that originate from embryonic remnants of Rathke’s pouch in the sellar region
What structure arises from Rathke’s pouch?
Anterior pituitary gland
Are craniopharyngiomas benign or malignant?
Benign
Which patient group tend to be affected by craniopharyngiomas?
Children
What are the most common paediatric supratentorial tumours?
Craniopharyngiomas
What does supratentorial mean?
The upper aspect of the brain
What clinical feature is associated with craniopharyngiomas?
Bitemporal inferior quadrantanopia
What are the nine clinical features associated with brain tumours?
Nocturnal Headache
Headache Worse Upon Waking
Headache Worse Upon Coughing/Straining
Visual Field Defects
Unilateral Ptosis
Focal Seizures
Hemiparesis
Third & Sixth Cranial Nerve Palsies
Papilloedema
What do the clinical features of brain tumours indicate?
A raised intracranial pressure
What is hemiparesis?
It is unilateral weakness of one entire side of the body
What does hemiparesis indicate about the location of the brain tumour?
The side affected by weakness will be contralateral to the location of the tumour
What is papilloedema?
It is s swelling of the optic disc secondary to raised intracranial pressure
Why is papilloedema a clinical feature of brain tumours?
This is due to the fact that the sheath around the optic nerve is connected to the subarachnoid space
What investigation can be used to detect papilloedema?
Fundoscopy
What are the five features of papilloedema on fundoscopy?
Blurring of the optic disc margin
Elevated optic disc
Loss of venous pulsation
Engorged retinal veins
Haemorrhage around the optic disc
Paton’s lines
What is optic disc elevation?
It occurs when the retinal vessels curve over the raised optic disc
What are Paton’s lines?
They are radiating lines around the optic disc
What is third cranial nerve palsy?
It is defined as decreased function of the third cranial nerve, resulting in paralysis of the lateral rectus muscles and superior oblique muscles
What are the five clinical features of cranial nerve palsy?
Ptosis of the superior eyelid
Down + out eyeball position
No pupillary light reflex
Dilated pupil
No accommodation
In which eye do the clinical features of third cranial nerve palsy present in?
The ipsilateral eye
What is sixth cranial nerve palsy?
It is defined as reduced function of the sixth cranial nerve, resulting in paralysis of the lateral recuts muscle
What is the clinical feature of sixth cranial nerve palsy?
Medial deviation of the affected eye
This means that the eye is unable to abduct
What three investigations are used to diagnose brain tumours?
MRI Scan
PET Scan
Brain Biopsy
What is the gold standard investigation used to diagnose brain tumours?
MRI scan
Which contrast is commonly used in MRI scans of the brain?
Gadolinium based contrast
How do brain tumours generally present on PET scans?
The cancerous growths will uptake more of the radioactive tracer compared to areas of normal tissue
What investigation is contraindicated when diagnosing brain tumours? Why?
Lumbar puncture
Brain tumours result in a raised intracranial pressure. If a lumbar puncture is conducted in patients who have a raised intracranial pressure, it can lead to herniation syndrome
What is herniation syndrome?
It occurs when brain tissue, blood and CSF shift from their normal position inside the skull
What are the four management options for brain tumours?
Surgical Management
Radiotherapy Treatment
Radiosurgery
Chemotherapy Treatment
What is the first line management option for brain tumours?
Surgical management
What are the two surgical procedures used to manage brain tumours?
Partial resection
Total resection
When are partial resection surgeries used to manage brain tumours?
When brain tumours are located near sensitive areas
OR
When they are unable to be completely separated from surrounding tissue
When are total resection surgeries used to manage brain tumours?
When brain tumours are small and easy to separate from surrounding brain tissue
What is radiation therapy?
It uses high-powered energy beams to kill cancer cells
When is radiation therapy used to manage brain tumours?
It is usually combined with chemotherapy to treat cancer in cases where patients are unsuitable for surgery
What radiotherapy is used when the brain tumour is proximal to sensitive areas within the brain?
Proton radiotherapy
What is radiosurgery?
It involves the use of multiple beams of radiation to give a highly focused form of radiation treatment to kill the tumour cells in a very small area
The power of each beam is very small, however at the point of the brain tumour where all the beams meet, a large dose of radiation is received to kill the tumour cells
What is chemotherapy?
It uses drugs to kill cancer cells
When is chemotherapy used to manage brain tumours?
It is usually prescribed adjuvantly in cases of glioma or metastatic brain tumours
What are the three chemotherapy agents used to manage brain tumours?
Temozolomide
Cisplastin
Methotrexate
What is the main chemotherapy agent used to manage brain tumours?
Temozolomide
