Pathology of Intracranial Tumours Flashcards
What are the anatomical considerations for ICP?
Falx cerebri and tentorium cerebelli
Foramen magnum
What are some causes of raised intracranial pressure?
Localised lesions - haemorrhages, tumours and abscess
Generalised - oedema post trauma
What are localised lesions?
Space occupying lesions in head - SOL
Tumours, haemorrhages and abscess
What is the effects of intracranial space occupying lesions?
Amount of tissue increases and raises ICP
Causes internal shift (herniation) between intracranial spaces
What is uncal herniation?
Cerebrum moves inferiorly over edge of tentorium
What is coning?
Cerebellum moves inferiorly into foramen magnum
What is a subfalcine herniation?
Under falx cerebri
There is a midline shift
Cingulate gyrus is pushed over to side and herniates underneath falx
Lateral ventricle is crushed flat and displaced downwards
What does swelling and shift of brain tissue cause?
Localised ischaemia
What are the symptoms and signs that there is pressure on brain?
Morning headaches and brainstem - squeeze on cortex and brainstem
Papilloedema - squeeze on optic nerve
What happens if pressure continues to increase?
Pupillary dilation - CNIII is squeezed
Falling GCS - squeeze on cortex and brainstem
Brainstem death - squeezing down into foramen magnum
Describe the classification of intracranial tumours
Primary - benign or malignant
Metastatic - breast, lung, kidney, colon and melanoma
What are brain cell tumours?
Gliomas and medulloblastoma (embryonic neuronal cells)
What are tumours from cells surrounding or originating outside the brain?
Meningioma, schwannoma, neurofibroma, adenoma, lymphoma, and hemangioblastoma
What are malignant intracranial tumours?
Gliomas
Medulloblastoma - childhood malignant tumour
What are the most common sites for CNS tumours?
Adult is above tentorium
Child is below
Describe gliomas
Glial differentiation
Diffuse edges - not encapsulated
Malignant but does not metastasis outside of CNS
Can be from astrocytes, oligodendrocytes and ependymal cells
Describe astrocytoma
Can be low grade or glioblastoma (2 extremes)
Astrocytoma grows very slowly and bland cells on microscopy
Glioblastoma is cellular, atypical and necrosis under microscope. Grows quickly
Describe a medulloblastoma
Tumour of primitive neuroectoderm (primitive neural cells)
Sheets of small undifferentiated cells
Children esp.
Posterior fossa and esp. brainstem
Describe a meningioma
From arachnocytes
Is benign so does not metastasis but can still be locally aggressive and can invade skull
Slow growing and often resectable
What is meningioma like under microscopy?
Bland cells forming small groups sometimes with calcification
Calcification sometimes called a psammoma body
Describe nerve sheath tumours
Around peripheral nerves - intracranial and extracranial
Schwannoma
What is acoustic neuroma?
8th vestibulocochlear nerve schwannoma at angle between pons and cerebellum
Unilateral deafness and benign lesion
Removal is difficult
Describe a pituitary adenoma
Benign tumour of pituitary fossa
Often secrete a pituitary hormone
Grow superiorly and impinge on optic chiasma - visual signs
Describe CNS lymphoma
High grade neoplasm
Usually diffuse large B cell lymphoma
Often deep and cortical site brain
Generally do not spread outside of CNS
Describe hemangioblastoma
Tumour of blood vessels, space occupying, may bleed and most often in cerebellum
Describe secondary tumours
Mostly carcinomas, common
Histology is that of primary tumours
