General points

Clinical presentation

• very variable according to parts of brain involved and nature of the tumour
• symptoms can be caused by local brain invasion, raised intracranial pressure and compression of adjacent structures
• headache – dull, constant or throbbing, progressive, may be worse at night waking the patient
• seizures – nature depends on location of tumour
• focal deficits – weakness, sensory loss, aphasia

Investigation

• full neurological exam to evaluate any potential deficits +/- ophthalmoscopy if suspecting raised intracranial pressure
• MRI + contrast
• biopsy required for histopathologic diagnosis and grading

Management

• often requires complex decision by multidisciplinary team, considering relative benefits of neurosurgery, radiotherapy and chemotherapy
• depending upon tumour site, endocrine or ophthalmological input may also be required
• options for treating symptoms: dexamethasone if significant oedema causing symptoms (avoid if suspecting lymphoma); anti-epileptics

 

 

Brain Metastases

• commonest form of brain tumour
• increasing incidence of brain metastases due to better treatment of primary tumours/patients surviving longer
• common primary sites = lung, melanoma, breast
• very variable presentation – low threshold for investigating people with known primary cancer

Imaging

• usually rounded, well circumscribed masses
• CT brain + IV contrast – contrast needed to show up mets
• +/- MRI – for solitary lesions to assess resectability, also for better brainstem visualisation
• staging CT

Management

• whole brain radiotherapy
• poor prognosis – aggressive treatment only considered in very young/fit patients
• neurosurgery indications: ≤3 metastases, palliation of hydrocephalus/debulking large metastases, biopsy for histological Dx (if unknown 1ry)
• stereotactic radiosurgery – gamma knife, linear particle accelerator

 

 

Primary brain tumours

Meningioma

• approximately 1/3 primary CNS tumours
• more commonly older and female patients
• associations – radiation exposure, neurofibromatosis type 2
• attached to dura (10% arise in spinal cord)
• slow growing, often asymptomatic and discovered incidentally (so true incidence may be even higher than current estimations)
• MRI – homogeneous contrast enhancement after gadolinium
• Management – small tumours can be managed conservatively, large or symptomatic tumours may require surgery

 

 

Gliomas

General points

• approximately 1/3 primary CNS tumours
• gliomas generally fast growing and in younger patients
• many different types depending upon glial cell of origin
• management – usually aim for full resection of tumour where possible

Astrosytoma

• grades I+II = commoner in children
• grade IV = glioblastoma multiforme – commonest adult form, heterogeneous appearance, very poor prognosis

Oligodendroglioma

• better prognosis than astrocytomas
• characteristic molecular abnormalities: IDH1/2 mutation & co-deletion of chromosomal arms 1p and 19q

Ependymoma

• arise from cells lining ventricles
• obstructive hydrocephalus a potential complication
• generally low-grade, but commonly more aggressive in children with posterior fossa tumour

Schwannoma

• usually benign (only 1% malignant)
• commonly affecting cranial nerves (i.e. intracranial but peripheral nervous system – Schwann cells myelinate peripheral nerves)
• common site = cerebropontine angle
• vestibular schwannoma (acoustic neuroma) = schwannoma of CN VIII – usually older patients, cause sensorineural hearing loss +/- tinnitus
• neurofibromatosis 2 → younger patients with bilateral acoustic neuroma
• other CNs affected: V > VII > IX/X/XI

Craniopharyngioma

• very rare, arising from remnants of Rathke’s pouch – migrates between nasopharynx and diencephalon
• more common in children
• visual symptoms caused by compression of optic chiasm – commonly inferior visual field defect due to superior compression

 

n.b. key facts:

• tumour located next to skull/attached to dura → meningioma
• tumour attached to ventricle wall → ependymoma
• bilateral vestibular schwannomas in young patient → neurofibromatosis type 2