Neurooncology

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

 

Image result for meningioma

Menigioma – image from Wikimedia Commons, used under creative commons license.

meningioma

Meningioma – image from radpod.org, used under creative commons license.

 

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
Image result for glioblastoma multiforme

Glioblastoma multiforme – image from radpod.org, used under creative commons license.

Image result for glioblastoma multiforme

Glioblastoma multiforme – image from Wikimedia Commons, used under creative commons license.

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
Image result for Ependymoma

Ependymoma – image from Wikimedia Commons, used under creative commons license.

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
Image result for Schwannoma

Vestibular Schwannoma – image from radpod.org, used under creative commons license.

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
Image result for Craniopharyngioma

Craniopharyngioma – image from radpod.org, used under creative commons license.

 

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