Pathology of Brain Tumours Flashcards
What are the causes of raised intracranial pressure?
Localised lesions: -Haemorrhage -Tumour -Abscess Generalised pathology: -Oedema post trauma
What are the effects of intracranial space occupying lesions?
Amount of tissue increases
Raises intracranial pressure
Causes internal shift/herniation between the intracranial spaces
Where can the brain herniate to as a result of intracranial space occupying lesions?
Right-left or left-right shift
Cerebrum moves inferiorly over edge of tentorium (uncal herniation)
Cerbellum moves inferiorly into foramen magnum (coning)
How does swelling lead to ischaemia within the brain?
Tumours squeeze nearby tissue and cause local ischaemia
What are the symptoms of pressure on the cortex and brainstem?
Morning headaches and sickness
What are the symptoms of pressure on the optic nerve?
Papilloedema
What signs are seen as intracranial pressure increases?
Pupillary dilation- squeeze and stretch on cranial nerve III
Falling GCS- squeeze on cortex and brainstem
Brain stem death- squeezing downwards of cerebellum into foramen magnum with crushing of brainstem
What are tumours of the glial cells known as?
Gliomas
What are tumours of the arachnoidal cells known as?
Meningioma
What are tumours of the nerve sheath cell known as?
Shwannoma or neurofibroma
What are tumours of the pituitary gland known as?
Pituitary gland adenomas
When are CNS tumours more common above and below the tentorium?
Majority above tentorium in adults
Majority below tentorium in children
What are the characteristics of a glioma?
Resemble cells of glial differentiation
Diffuse edges and not encapsulate
Malignant but do not metastasis outside the CNS
What are the two main kinds of astrocytoma?
Low grade astrocytoma
Glioblastoma
How are low grade astrocytomas characterised?
Bland cells on microscopy- similar to normal astrocytes
Grow very slowly
What are the characteristics of a glioblastoma?
Cellular, atypical tumour with necrosis under microscope
Grow quickly and often present as large tumours
What are the characteristics of a medulloblastoma?
Tumour of primitive neuroectoderm
Sheets of small undifferentiated cells
More common in children
Common in posterior fossa, especially the brainstem
From what cells do meningiomas arise?
Arachnocytes
What are the characteristics of a meningioma?
Slow growing
Often resectable
Benign but can be locally aggressive and invade skull
Microscopy- bland cells forming small groups that sometimes have calcification
What are the characteristics of nerve sheath tumours?
Around peripheral nerves both intracranially and extracranially
Schwannoma is an example
What kind of tumour is an acoustic neuroma and how would it present?
Schwannoma of the vestibulocochlear nerve
Unilateral deafness
Benign lesion but removal technically difficult
What are the characteristics of a pituitary adenoma?
Benign tumour of the pituitary
Often secrete a pituitary hormone
Can grow superiorly and impinge on optic chiasma and give visual signs
What are the characteristics of a CNS lymphoma?
High grade neoplasm
Usually diffuse large B-cell lymphoma
Often deep and central site in brain
Generally do not spread outside of CNS
What are the characteristics of a haemangioblastoma?
Tumour of the blood vessels
Space occupying
May bleed
Most often in cerebellum
