🎯 Fundamentals

• metastatic brain tumours are more common than primary brain tumours

  • lung cancer is the most common cancer that metastasises to the brain

  • breast cancer and melanoma can also metastasise to the brain

  • metastases are usually multiple and therefore difficult to treat via surgical intervention

  • dexamethasone is initially given to treat brain metastases

 

Clinical features of brain tumours

• headache

• focal neurological deficits

  • signs and symptoms depend on the area of the brain affected

• seizures

• raised intracranial pressure

  • nausea and vomiting

  • visual disturbances

  • altered mental status

 

Assessment 

• best neuroimaging modality

  • MRI with gadolinium contrast to help with the visualisation of tumours

  • CT to visualise lesions of the skull

 

Classification of primary brain tumours

• pituitary tumours

  • pituitary adenoma

  • craniopharyngioma

• Anterior tumours (common in Adults)

  • glioblastoma multiforme

  • meningioma

  • oligodendroglia

  • vestibular schwannoma (acoustic neuroma)

• Posterior tumours (common in Paediatrics)

  • medulloblastoma

  • pilocytic astrocytoma

  • haemoangioblastoma

  • ependymoma

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⚡️ Primary brain tumours​

 

Pituitary adenoma

• benign tumours of the pituitary gland

• classification

  • can be functional (excessive hormone secretion) or non-functional (non-secretory)

  • can be a macroadenoma (> 1 cm) or a microadenoma (< 1 cm)

• can compress the superior aspect of the optic chiasm causing a bitemporal hemianopia with an upper quadrant defect

 

Craniopharyngioma

• benign brain tumour that occurs near the pituitary gland and hypothalamus

• derived from the remnants of Rathke’s pouch (the area from which the anterior pituitary gland develops

• the tumour can affect the hypothalamus which has a central role in regulating body temperature, appetite, thirst and sleep

• it compresses the inferior aspect of the optic chiasm causing a bitemporal hemianopia with an lower quadrant defect

 

Glioblastoma multiforme

• most common primary tumour in adults (> 45%)

• fast-growing

• malignant (cancerous)

• prognosis is poor (median survival is 15 months)

 

Meningioma

• second most common primary tumour in adults

• arises from the meninges of the brain and spinal cord (specifically the meningothelial arachnoid cap cells)

• associated with neurofibromatosis type 2 where there is a genetic mutation on chromosome 22

• seen as extra-axial masses on imaging (meaning that the lesions are external to the brain parenchyma)

 

Oligodendroglioma

• commonly seen in the frontal lobes

• has a “fried egg” appearance on histology

• constitutes about 5% of intracranial primary tumours

 

Vestibular schwannoma (acoustic neuroma)

• arises from the vestibulocochlear nerve (CN VIII)

• it can affect the trigeminal (CN V) and facial nerves (CN VII)

• usually found at the cerebellopontine angle

• bilateral vestibular schwannomas are associated with neurofibromatosis type 2

 

Medulloblastoma

• develops below the tentorium cerebelli in the posterior cranial fossa

  • usually originates in the cerebellum and can spread into the 4th ventricle causing a non-communicating hydrocephalus

  • this can cause signs and symptoms of raised intracranial pressure

• symptoms are also due to the compression of the cerebellum

  • ataxia, slurred speech, intention tremor, hypotonia, nystagmus, dysdiadochokinesia

 

Pilocytic astrocytoma

• most common childhood primary brain tumour

• complete resection is usually curative

 

Haemangioblastoma

• associated with von Hippel Lindau syndrome

 

Ependymoma

• ependymal cells line the ventricular system in the brain

  • an ependymoma is a tumour of these cells