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MBBS IV - Junior Clerkship WCS > JC28 (Surgery) - Brain Tumors > Flashcards

JC28 (Surgery) - Brain Tumors Flashcards

1
Q

Primary brain tumours by cellular origin

A 
Meninges - meningioma 
Neuroepithelial tissue - astrocytoma, glioblastoma 
Sellar - Pituitary adenoma 
Nerve sheath - Schwannoma, neurofibroma 
Neurons - gangliocytoma 
Ventricles: Ependymoma 
Embryonal - Medulloblastoma

Others: Lymphoma, germinoma, teratoma…etc
Metastatic tumor

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2
Q

Ddx brain tumors (diseases with similar clinical presentation)

A

Space occupying lesions:
- Tumor and Peri-tumoral edema
- Abscess, Tuberculoma
- Haematoma

Vascular
- Ischemic Stroke, infarct
- Hypoxic ischemic encephalopathy
- Hemorrhagic stroke
- SAH
- TBI, contusion

Hydrocephalus

Seizures (many types)

Misc:
- Sarcoidosis
- Cystic disease: arachnoid or parasitic
- Idiopathic Intracranial Hypertension

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3
Q

Routes of tumor metastasis to brain

A

Direct infiltration
Haematogenous
CSF

(Not lymphatics*)

Secondary metastasis to brain is most common in adults**

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4
Q

Common primary tumors and distribution between supratentorial and infratentorial fossa in adults

A

Supratentorial fossa = 85%
e.g.Secondary metastatic tumor ,Glioma ,Meningioma

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5
Q

Common primary tumors and distribution between supratentorial and infratentorial fossa in children

A

Medulloblastoma
Cerebellar astrocytoma
Ependymoma
Germ cell tumor

Infratentorial/ posterior fossa = 60%

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6
Q

Mass effects of brain tumor

A

Raised ICP symptoms, herniation

Focal neurological deficits: neuronal destruction, pressure effect, edema

Symptoms specific to site: e.g. acoustic neuroma - deafness and tinnitus, trigeminal schwannoma - Trigeminal nerve neuralgia …etc

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7
Q

Mechanisms of raised ICP due to brain tumor

A

Mass effect

Peritumoral edema

CSF outflow obstruction (non-communicating hydrocephalus)

Venous congestion (e.g. dural venous sinus congestion by meningiomas)

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8
Q

Explain why seizures are specific to supratentorial lesions

2 examples of structural epilepsy

A

Cerebellar cortex (infra-tentorial) is inhibitory in nature, unlikely for tumor to cause neuronal hyperactivity

Temporal lobe epilepsy from Mesial Temporal Sclerosis
Gelastic seizures from hypothalamic harmatoma

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9
Q

Symptoms and signs of brain tumours

A

Increased ICP and herniation: Generalized, dull, constant headache (worse in morning), vomiting, ↓consciousness

Papilloedema, Cushing’s triad (late features)

Seizures

Cognitive dysfunction and neurological deficits

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10
Q

Typical type of seizure associated with brain tumors

A

Repetitive and stereotyped seizures

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11
Q

4 modalities of imaging for clinically suspected brain tumor

A

CT brain +/- contrast

MRI with contrast ***

MR Spectroscopy (diff. high grade and low grade by chemical composition)

PET scan (systemic malignancy screen)

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12
Q

CT brain shows enhanced mass, list some ddx

A

Enhancement indicates
- Outside BBB, eg. meningioma (homogenously enhancing)

  • Disruption of BBB, eg. high-grade tumours, stroke,inflammation
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13
Q

How to differentiate Low-grade vs high-grade brain tumors e.g. glioma

A

Differentiate with MR Spectroscopy

e.g. glioma
High-grade glioma: ↓T1W, heterogenous* enhancement with surrounding vasogenic edema* (↑T2W) ± central necrosis*

Low-grade glioma: ↑T2W, non-enhancing* expansile lesion with NO surrounding vasogenic oedema

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14
Q

Describe MRI appearance of primary intracranial lymphoma (/)

A

solitary/multifocal T2W-iso/hypointense,

contrast-enhancing lesions in subcortical regions,

classically a/w prominent diffusion restriction on DWI

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15
Q

Describe MRI appearance of metastatic brain tumor

A

Brain mets:

round, well-circumscribed, contrast-enhancing lesion** (variable signal on T1/2W images)

± surrounding oedema (if large),

involve multiple regions/ intracranial compartments**

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16
Q

Describe MRI appearance of meningioma

A

extra-axial, dura-based*
T1W-hypo/isointense, T2W-iso/hyperintense lesion
with strong homogenous* enhancement

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17
Q

2 modalities of imaging for surgical planning for brain tumor resection

A

Functional imaging: for pre-operative planning
□ Functional MRI (fMRI):
identify important cortical areas to guide surgical resection

□ MRI diffusion tension imaging (DTI, tractography):
identify important tracts to guide surgical resection

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18
Q

Medication therapies for brain tumors (relieving symptoms and peri-operative management)

A

Anticonvulsants: treatment/ Secondary prophylaxis of seizures, usually levetiracetam (Keppra)

High-dose glucocorticoids: reduction of cerebral oedema for palliation, or post-radiation therapy, usually dexamethasone

Tranexamic acid - perioperative reduction in bleeding

19
Q

Modalities of treatment for brain tumours (5)

A
  • Medical therapy
  • Surgery
  • Radiotherapy
  • Chemotherapy
  • Targeted therapy
20
Q

5 surgical approaches for accessing brain tumors

A

→ Craniotomy: flap of bone cut and reflected
→ Burr hole: often for biopsy
→ Craniectomy: burr hole + removal of surrounding bone
→ Transphenoidal (pituitary)
→ Transoral (anterior tumours)

21
Q

Surgical procedures for

  • pathological diagnosis
  • removal of tumor
  • hydrocephalus
A

Stereotactic biopsy (usu. non-resectable tumors) or Burrhole bx for pathological diagnosis

Surgical resection for cytoredection and functional preservation

CSF shunting for hydrocephalus (VA/VP shunts) or EVD

22
Q

5 intra-operative guidance techniques for surgical resection of brain tumors

A
  1. Frameless stereotaxy - localization of probe and structures with fMRI or tactography
  2. Real-time intraoperative MRI
  3. Evoked potential for electrophysiological monitoring (e.g. BAEP)
  4. Awake craniotomy with electrical stimulation of cortex
  5. 5-ALA guided resection (tumor cell glow under UV light)
23
Q

General post-operative complications after brain tumor removal

A

→ Haemorrhage, brain swelling, hydrocephalus
→ Seizure, new neurological deficit
→ Infections

24
Q

4 modalities of rehabilitation after brain surgery

A

physiotherapy, occupational therapy,

speech therapy, clinical psychology

25
Q

3 types of radiotherapy for treatment of brain tumors

A

□ External beam radiotherapy (ERT):
standard radiotherapy with parallel rays

□ Interstitial brachytherapy: radioactive source
placed within brain (rarely used)

□ Stereotactic radiosurgery (SRS):
Multiple converging beams to focus on a selected
target
X-knife, Gamma knife, Cyberknife

26
Q

Acute complications of cranial irradiation

A

Fatigue, loss of appetite (very common)

Headache: typically mild

Nausea/vomiting

Initial worsening of prior neurological S/S due to reactive swelling

Radiation dermatitis and alopecia

Acute encephalopathy (uncommon but severe)

27
Q

Chronic complications of cranial irradiation

A

Radionecrosis: typically 1-3y after RT

Neurocognitive deficits

Vasculopathy and ischaemic stroke

Hypopituitarism*

Ocular toxicity: cataract, optic neuropathy, dry eye

Ototoxicity due to SN hearing loss

28
Q

Most common origins of metastatic brain tumors

Distribution of intracranial sites for metastatic tumors

A

lung (16-20%), breast (5%), RCC (7-10%), colorectal (1-2%), melanoma (7%)

~80% cerebral hemisphere, ~15% cerebellum, ~5% brainstem
Commonest at watershed area between major arterial supplies and grey-white junction

29
Q

Imaging features suggestive of metastatic brain cancer

A

multiple lesions, grey-white jx location, circumscribed margin, large volume of vasogenic oedema compared to size of lesion

30
Q

Indications for surgical removal of brain tumor

A

→ Solitary operable lesion
→ Young pt with good function and reasonable life expectancy
→ Stable systemic disease with good treatment if secondary metastasis

31
Q

4 histological types of localized astrocytoma (4) (/)

A

Pilocytic astrocytoma (I)
Subependymal giant cell astrocytoma (I)
Pleomorphic xanthoastrocytoma (II)
Anaplastic pleomorphic xanthoastrocytoma (III)

32
Q

3 histological types of diffuse astrocytomas (/)

A 
Diffuse astrocytoma (II)
Anaplastic astrocytoma (III)
Glioblastoma (IV)
33
Q

Management options for astrocytoma/ glioma

A
  • Watchful waiting for low-grade astrocytoma

First line:

  • Surgical removal
  • Temozolomide- based chemoradiation and external RT post-op

Second line:

  • Anti-angiogenesis agent, eg. bevacizumab
  • Tumor treating field (TTF): electrical field treatment
34
Q

Glioblastoma multiforme

  • tumor cell origin
  • Growth pattern
  • Prognosis
A

Undifferentiated glial cells or pre-existing astrocytomas

Infiltrative: into ventricular system and subarachnoid space

Poor prognosis: mean lifespan 14 months

35
Q

Pituitary adenoma

  • size cut-off
  • Clinical presentation
A

macro- (>1cm) vs micro (<1cm)

Presentation:

  • Visual: bitemporal hemianopia
  • Hormonal hyper/hyposecretion (ACTH, GH, Prolactin)
  • Cranial nerve palsy
  • Bleeding (apoplexy)
  • Hydrocephalus at 3rd ventricle
36
Q

Management options for functional pituitary adenoma

A

□ Observation for non-secreting microadenoma
□ Dopamine agonist as 1st line for prolactinoma

□ Surgery Indications:

  • Symptomatic/large non-secreting adenoma
  • ACTH- or GH-secreting adenomas
  • Second-line for prolactinoma (if refractory to medical Rx)
37
Q

2 surgical approaches for pituitary adenoma resection

A

Approach:

  • Transcranial (Craniotomy)
  • Transphenoidal (transnasal or sublabial) via endoscopic/ microscopic
38
Q

Management options for non-functional pituitary tumors

A

Watchful waiting for micro-incidentaloma, routine MRI

Hormone testing, visual field testing and routine MRI for macro-incidentaloma

Surgery or radiosurgery for symptomatic changes

39
Q

Pituitary apoplexy

  • Cause
  • Presentation
  • Imaging
  • Management
A

Cause: haemorrhagic infarction of a tumour

Presentation: sudden or subacute (over 1-2d) onset of
→ Excruciating headache
→ Diplopia due to pressure on CN III
→ Hypopituitarism (esp adrenal crisis)
→ ± visual defects, vertigo and altered consciousness

Imaging: hyperdensity (acute blood) in pituitary region on CT

Mx: surgical decompression under steroid cover

40
Q

Complications of transphenoidal surgery

A

Complications of transsphenoidal surgery:

  • Endocrine: diabetes insipidus, hypopituitarism
  • Vision loss
  • CSF leakage and meningitis
  • Vascular injury and CVA
  • ENT symptoms
  • Intracranial haemorrhage
41
Q

Classical CT appearance of meningioma

A

→ Well-circumscribed dural-based lesion (with ‘dural tail’)

→ Homogenous enhancement

42
Q

Symptoms and signs of acoustic neuroma (vestibular schwannoma)

A

→ Cochlear n. (95%): SN hearing loss, tinnitus
→ Vestibular nerve (61%): unsteadiness, mild vertigo
(typically NOT severe spinning vertigo due to gradual onset and compensation)
→ Trigeminal n. (17%): facial numbness, hyperesthesia, pain

(NO facial n. involvement)

43
Q

Investigation and management of acoustic neuroma (vestibular schwannoma)

A

□ Ix: Pure tone audiometry (95% abnormal), MRI contrast (Cerebellar pontine angle tumour with enhancement)

□ Mx:

  • surgery/ radiosurgery
  • observation if old + small + limited hearing loss

MBBS IV - Junior Clerkship WCS (131 decks)

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