Pathology of Brain Tumours Flashcards
What is meant by intracranial pressure?
The cranium is a hard, rigid, closed box and for pressure to be stable there must be (within certain limits) the correct amount of braintissure/blood/CSF
There are thick tough fibrous sheets inside that keep the brain in place, what is A and what is B?
A - falx cerebri
B - tentorium cerebelli
Can the brain go through the falx cerebri?
Brain cannot go through falx, but can go round edge
e.g. if pressurised
Can the brain go through the skull?
Brain cannot go through skull, but can move down through foramen magnum
What is the consistency of the brain like?
Brain is soft – like a jelly – so it can move easily
What are the 2 main types of causes for raised intracranial pressure?
localised lesions
generalised pathology
What are some examples of localised lesions that may be the cause of raised intracranial pressure?
Haemorrhage (if localised called a haematoma)
Tumour
Abscess
What are some examples of generalised pathology that may be the cause of raised intracranial pressure?
Oedema post traums
Localised lesions = __________________ in head = SOL
Localised lesions = Space Occupying Lesions in head = SOL
- Tumours
- Bleeding (haematoma)
- Abscess
What are the effects of intracranial space occupying lesions? (SOL)
As the amount of tissue increases, intracranial pressure rises
Cause internal shift (herniation) between the intracranial spaces:
- Right-left or left-right
- Cerebrum moves inferiorly over edge of tentorium (uncal herniation)
- Cerebellum moves inferiorly into foramen magnum (coning)
Image showing Tentorial (uncal) herniation
Image showing Cerebellar tonsillar herniation
Crush important nuclei like respiratory and cardiac centres and you die
What does swelling and shifting of brain tissue lead to?
Swelling and shift = localised ischaemia
Tumours squeeze nearby tissue and cause local ischaemia
Pressur eon the brian has consequences, what are symptoms and signs seen?
squeeze on the cortex and brainstem = morning headaches and sickness - very important symptom
squeeze on the optic nerve = papilloedema (seen on fundoscopy of the eye)
As pressure on the brain increases, what symtpoms may be seen?
Pupillary dilation - Squeeze and stretch on cranial nerve 3
Falling Glasgow coma scale - Squeeze on cortex and brainstem
Brain stem death – squeezing downwards of cerebellum into foramen magnum with crushing of brainstem
What are different types of intracranial tumours?
Central nervous system:
- Primary tumours
- Secondary (metastatic tumours)
Other intracranial tumours:
- Cells originating outside brain and spinal cord (eg meningioma)
What are the 2 different classifications of intracranial tumours?
Primary (benign and malignat)
Metastatic malignancy (rare in children)
How are primary intracranial tumors named?
by resembelence of the cell of origin
What is a tumour of glial cells called?
gliomas (glioblastoma, astrocytoma, oligodendroglioma, ependymoma)
What is a tumour of embyronic neural calls called?
medulloblastoma
Nerve cell tumours are rare so tends to be embryonic neural cells as adults ones don’t change and divide and tend to be cell cycled block so only primitive neurons can form tumours
What is a tumour of arachnoidal calls called?
meningioma
What is a tumour of nerve sheath calls called?
Schwannoma, neurofibroma
What is a tumour of the pituitary gland called?
adenoma
What is the tumour of lymphoid cells called?
lymphoma
What is a tumour of capillary vessels called?
haemangioblastoma
Where may a intracranial metastatic malignancy originate from?
Breast, lung, kidney, colon, melanoma
What are tumour of brain cells?
Glial cells – gliomas (glioblastoma, astrocytoma, oligodendroglioma, ependymoma)
Embryonic neural cells – medulloblastoma
What are tumours of cells surrounding or originate outside the brain?
Arachnoidal cell – meningioma
Nerve sheath cell – Schwannoma, neurofibroma
Pituitary gland - adenoma
Lymphoid cell – lymphoma
Capillary vessels - haemangioblastoma
What are malignant intracranial tumours?
Glial cells – gliomas (glioblastoma, astrocytoma, oligodendroglioma, ependymoma)
What are intracranial childhood malignant tumours?
Embryonic neural cells – medulloblastoma
Where is the site of central nervous system tumours?
adults - majority run above tentorium
children - majority below tentorium
What do gliomas resemble?
Resemble cells of glial differentiation
What are the structures of gliomas?
Diffuse edges – not encapsulated
Are gliomas malignant and do they metastasise?
Malignant but do not metastasise outside the CNS
Cannot get through the blood brain barrier
Glioma - resemble cells of glial differentiation, whata re some exmaples?
Astrocytes = astrocytoma (including glioblastoma - very malignant type of astrocytoma)
Oligodendrocytes = oligodendroglioma
Ependymal cells = ependymoma
What is an astrocyte?
astrocyte = ‘star’ shaped cell
long processes support other cells structually and biochemically
What are the 2 types of astrocytoma?
- Low grade astrocytoma
- Glioblastoma
What is an astrocytoma – low grade?
Bland cells on microscopy (similar to normal astrocytes)
Grow very slowly
What is a glioblastoma?
most malignant astrocytoma (high grade on microscopy) = glioblastoma (sometimes called glioblastoma multiforme)
What are glioblastoma cells like?
Cellular, atypical tumour, with necrosis under microscope
Grow quickly - often present as large tumours
What is a medulloblastoma?
Tumour of primitive neuroectoderm (primitive neural cells)
Sheets of small undifferentiated cells
Children especially effected
Posterior fossa, especially brainstem
What is a meningioma?
form “arachnocytes” - cells that make up the coverings of the brain
They are slow growing and are often resectable
Are meningiomas benign or metastatic?
“Benign” – do not metastasise – but can be locally aggressive and can invade the skull
What do meningiomas look like on microscopy?
bland cells forming small groups, sometimes with calcification
What are nerve sheath tumours?
Around peripheral nerves – intracranial and extracranial
Schwannoma is one example
Normal schwann cells wrap around peripheral nerves and form electrical insulation
8th vestibulocochlear nerve schwannoma, often called ‘____________’ at angle between pons and cerebellum
8th vestibulocochlear nerve schwannoma, often called ‘Acoustic neuroma’ at angle between pons and cerebellum
What is an acoustic neuroma?
8th vestibulocochlear nerve schwannoma at the angle between pons and cerebellum
Causes unilateral deafness
Benign lesion but removal technically difficult as often wedged right up against the brain stem and near lots of very important structures
What is a pituitary adenoma?
Benign tumour of pituitary in pituitary fossa
Often secrete a pituitary hormone
Grow superiorly and impinge on optic chiasma – visual signs
What are the signs of a pituitary adenoma?
Grow superiorly and impinge on optic chiasma – visual signs
What is a CNS lymphoma?
High grade neoplasm
Usually diffuse large B-cell lymphoma
Often deep and central site in brain - difficult to biopsy
Difficult to treat as drug do not cross blood-brain barrier
Generally do not spread outside of CNS
What is a haemangioblastoma?
tumour of blood vessels
space occupying
may bleed
most often in cerebellum
Are secondary tumours common or rare and what type of tumour are they commonly?
common
mostly carcinomas
What is the histology of secondary tumours like?
like the histology of the primary tumour
