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JC WCS > Neurosurgery JC028: A Mass In The Brain: Brain Tumours > Flashcards

Neurosurgery JC028: A Mass In The Brain: Brain Tumours Flashcards

1
Q

Classification of Brain tumours

A

Primary
- Benign (e.g. Meningioma, Pituitary adenoma)
- Malignant (e.g. Glioblastoma)
- “Intermediate”
—> not always clear cut
—> histologically benign
—> tendency to recur / dedifferentiate into malignant lesions
—> e.g. some “low-grade” gliomas, craniopharyngioma

Secondary (Metastasis)

  • ***commonest lesions in adults
  • increasing frequency (∵ effective systemic therapy for extracranial malignancy —> “chronic disease”)
  • lung, breast, colon, ***melanoma (highest propensity)
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2
Q

Primary brain tumour by cellular origin

A

Important:

  1. Meninges: ***Meningioma
  2. Neuroepithelial tissue: **Astrocytoma, **Glioblastoma (GBM), ***Ependymoma
  3. Sellar: ***Pituitary adenoma
  4. Nerve sheath: Schwannoma, Neurofibroma

Others:

  1. Neuronal: Gangliocytoma
  2. Embryonal: ***Medulloblastoma
  3. Lymphoid cells: Lymphoma (esp. in immunocompromised patients e.g. HIV +ve)
  4. Germ cells: Germinoma, Teratoma
  5. Malformative tumour: ***Craniopharyngioma
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3
Q

Age, Location, Histology of brain tumours

A 
Adults:
- Supratentorial (e.g. Cerebrum)
—> ***Metastasis
—> Glioma
—> ***Meningioma
Children:
- Infratentorial (Cerebellum, Brainstem)
—> ***Medulloblastoma
—> Cerebellar astrocytoma
—> ***Ependymoma
—> Germ cell tumour
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4
Q

***Clinical presentation of brain tumour

A 
1. ↑ ICP
Causes:
- ***Mass effect
- Peri-tumoural edema
- ***CSF flow obstruction —> Non-communicating hydrocephalus
- ***Venous congestion (by Meningioma)

Effect:
- Brain herniation (Subfalcine, Central, Uncal, Tonsillar) —> Brainstem compression

2. Focal neurological deficits
Loss of function due to:
- Neuronal destruction
- Pressure effect
- Edema (reversible with steroids)
  • **Enables clinical localisation:
  • e.g. Aphasia (Broca’s area)
  • RLL weakness (Left motor cortex)
  • Truncal ataxia (Vermis cerebellum)
  • Dysmetria, Dysdiadochokinesia (Cerebellar hemisphere)
  • Cognitive decline / Personality change (Frontal lobe)
  1. Seizure
    - unknown mechanism
    - **Neuronal hyperactivity (uncontrolled cerebral discharges)
    - **    ONLY Supratentorial tumours (NOT in Infratentorial lesions, ∵ Cerebellum functionally is inhibitory)
    - Partial / Grand-mal (generalised tonic-clonic) seizure
    - Complex partial seizure
    - Mesial Temporal Sclerosis (affecting hippocampus) —> Temporal lobe epilepsy (TLE)
    - Hypothalamic harmatoma (malformation condition in children) —> Gelastic seizure
  2. Others specific to location
    - Acoustic neuroma (deafness, tinnitus)
    - Acoustic neuroma (hemifacial spasm)
    - Trigeminal schwannoma (CN5 neuralgia)
    - Pituitary adenoma (bitemporal hemianopia, hyper/hyposecretion of pituitary gland)
    - Craniopharyngioma (failure to thrive, precocious puberty)
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5
Q

Diagnosis of brain tumour

A
  1. **Contrast enhancement imaging
    - Contrast can leak into lesion via blood supply if BBB destroyed
    - Meningioma: **    intense **dura-based **homogenous enhancement (homogenous ∵ supplied by ECA —> no BBB)
    - Low-grade glioma: heterogenous weaker enhancement (∵ BBB not disrupted)
    - Malignant glioma: enhancement of lesion (∵ vascular + leaky BBB)
    (MR spectroscopy can also differentiate low grade / high grade via chemical composition: High choline = High cell turnover)
  2. PET
    - malignant lesion: tend to be Hypermetabolic
  3. **Functional MRI + **Diffusion Tensor Imaging (DTI) Tractography
    - based on metabolic activity / bloodflow
    - DTI: allow visualisation of tracts
    - Locate functionally important structures —> Aids surgical planning
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6
Q

Tumour haemorrhage

A

Tumour tends to be vascular

  1. Bleeding Glioblastoma
    - mimic Haemorrhagic stroke (can only differentiate on MRI)
  2. Pituitary Apoplexy
    - **acute visual loss
    - **    hormonal crisis
    - ***SAH
  3. Sellar tumour
    - mimic Cerebral aneurysm
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7
Q

Principles and Options of treatment

A

Principles:

  • Aim at cure if feasible
  • Preserve life
  • Preserve function
  • Preserve personhood
  • Maximise QOL
  • Do not treat scan

Treatment options:

  1. General medication
  2. Surgical biopsy + resection
  3. Radiotherapy
  4. Chemotherapy
  5. Targeted therapy
  6. Immunotherapy
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8
Q

Medication therapy

A
  1. Anticonvulsant (e.g. Phenytoin, Levetiracetam)
    - prophylaxis / treatment (if already seizure)
    - ***NOT for Infratentorial lesion
  2. Steroids (e.g. Dexamethasone)
    - exclude infection first
    - ↓ cerebral edema + relieve symptoms
    - peri-operative use / palliation
    - S/E: DM, immunosuppression, peptic ulcer
  3. Tranexamic acid
    - inhibitor of plasminogen activation
    - peri-operative to ↓ bleeding
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9
Q

Principles of Brain tumour surgery

A
  1. Obtain histological diagnosis
  2. Maximal safe removal
    - preserve life
    - preserve function
  3. ***“Resection margin” difficult

Main questions:

  1. Whether to resect
  2. When to resect
  3. How to resect
  4. How much to resect
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10
Q

Surgery techniques

A
  1. ***Craniotomy
  2. ***Neuronavigation + Microsurgery
  3. Awake craniotomy for ***Speech cortex mapping
    - electrical stimulation over speech cortex —> induces speech arrest —> allow mapping of speech cortex (∵ varies between people)
  4. ***Intraoperative MRI
    - confirm total removal
    - identify residual tumour

Monitoring:

  • **Electrophysiological monitoring —> alert surgeons of iatrogenic surgery
  • Somatosensory evoked potential (SSEP)
  • Motor evoked potential (MEP)
  • Brainstem auditory evoked potential (BAEP)
  • Motor mapping
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11
Q

Radiation therapy for brain tumour

A

Types:

  • Whole brain
  • Traditional
  • ***Stereotactic radiosurgery
  • Aim to deliver high treatment dose to tumour bed
  • Minimise radiation to normal tissue
  • Balance between treatment efficacy and SE
  • can treat both Benign + Malignant lesions
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12
Q

Radiosurgery

A

Focused radiation beams converge onto tumour

X-knife: uses X-ray
Gamma knife: uses gamma ray
Cyberknife: uses real-time imaging and moves to adjust to movement (e.g. lung movement)

Disadvantages:

  • ***Diffuse lesions respond less well
  • Radiation necrosis can occur
  • Size limit 2.5-3cm
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13
Q

Brain tumours

A
  1. Cerebral metastases
  2. Meningioma
  3. Neuroepithelial tumours / Glioma
  4. Pituitary adenoma
  5. Acoustic neuroma
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14
Q
  1. Cerebral metastasis
A
  • Commonest intracranial tumour overall
  • ↑ Incidence (∵ cancer survival improves)
  • Haematogenous / Direct invasion (LN metastasis non-existent)
  • Common origins: **Lung, Breast, Colon, Kidney, **Melanoma
  • May present ***before the primary disease
  • May develop when primary disease is long ***in remission + without extraneural metastasis
  • Multiple lesions in a cancer patient can be something else (e.g. **Toxoplasmosis, **CNS lymphoma, ***Cysticercosis (pork tapeworm))
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15
Q

Cancer patients presenting with solitary brain mass

A

Top DDx: Metastasis (but cannot presume)
Other DDx: Primary brain tumour, Abscess (immunocompromised due to chemotherapy)
- History + Examination crucial
- Look for primary + screen for other foci
- **SPECT
- Serum tumour markers (not very helpful)
- Surgery + **Histology if in doubt

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16
Q

Aim of Surgery for Brain metastasis and Patient selection

A

Aim:

  • Symptomatic palliation
  • Maintain / Improve QOL
  • Prolong life-expectancy
  • Cure uncommon but not impossible

Tend to resect if:

  • ***Single lesion (If multiple: Dexamethasone / WBRT)
  • Something to palliate
  • ***Low risk of causing deficit
  • Young + Fit
  • Systemic disease under control
  • ***Reasonable life expectancy
17
Q

Outcome of Brain metastasis

A

Median survival:

  • Untreated ~1 month
  • WBRT alone ~3-6 months
  • **Surgery + **WBRT >=12 months
  • Rarely surgery alone
  • WBRT has significant SE —> Radiosurgery is now preferred
  • Drugs that cross BBB (e.g. Chemotherapy) may improve outcome further
18
Q
  1. Meningioma
A
  • Arise from Arachnoid cap cells
  • Risk: **Female, Radiation-induced, **Neurofibromatosis type 2
  • Mostly benign (can be Atypical / Malignant)

Imaging:

  • Dura-based lesion with Dura tail
  • Strong **homogenous with **intense contrast enhancement

Treatment:

  1. Surgery (1st choice) (easy / very difficult e.g. encasing ICA)
  2. Radiosurgery (effective)

Prognosis:

  • Generally good outcome
  • Recurrence ~15%
19
Q
  1. Neuroepithelial tumours / Glioma
A

Arise from Astrocytes, Oligodendrocytes, Ependymal cells etc.

Common:
Astrocytoma (WHO grade 1-4)
- Grade 4: Glioblastoma multiforme (GBM)
—> middle-aged or above
—> extremely malignant: infiltrative, rapid growth, invasive
—> almost always recur
—> life expectancy ~14 months

Treatment of malignant glioma

  • WHO grade 3/4 glioma
    1. Maximal safe surgical removal where feasible
  1. **Chemoirradiation with **Temozolomide (TMZ)
    - standard therapy
    - alkylating agent
    - Concomitant TMZ + Early radiotherapy (ERT), then adjuvant TMZ
  2. ***Anti-angiogenesis agents (e.g. Bevacizumab)
  3. ***Tumour Treating Field (TTF)
    - generate electric fields which interfere with cell division (esp. to actively dividing cells ∵ disrupt alignment of microtubules)
20
Q
  1. Pituitary adenoma
A
  • 20-25% at autopsy
  • Micro (<1cm) / Macro
  • Functioning / Non-functioning

Common presentation:

  1. ***Visual (Bitemporal hemianopia)
  2. ***Hormonal (Hyper / Hyposecretion)
  3. ***CN palsy (if extend into Cavernous sinus)
  4. Bleeding (Apoplexy)
  5. Hydrocephalus (at 3rd ventricle)

Treatment:
Hyperfunctioning
—> Prolactinoma —> ***Dopamine agonist (Bromocriptine, Cabergoline)
—> Others —> Surgery / Medical (GH, ACTH, TSH: Surgery first)

Non-functioning
—> Micro-incidentaloma —> Repeat MRI —> Tumour growth, Visual field abnormality —> Surgery / Radiosurgery

—> Macro-incidentaloma —> VF testing, Hypopituitarism
—> Normal —> Repeat MRI, Pituitary function, VF —> Tumour growth, Visual field abnormality —> Surgery / Radiosurgery
—> Abnormal —> Surgery / Radiosurgery

Surgical approaches:

  1. Craniotomy (***Transcranial approach)
    - mainly when significant suprasellar extension
  2. Microscopic / Endoscopic (***Transsphenoidal approach)
    - less invasive but depends on tumour size + morphology
21
Q

Complications of Transsphenoidal surgery

A
  1. **Hypopituitarism
    - lack of Cortisol —> **    shock
  2. ***Diabetes insipidus
    - lack of ADH —> polyuria, haemoconcentration
  3. **CSF leakage + Meningitis
    - CSF rhinorrhoea
    - can occur in delayed fashion
    - CT scan: Air in head, **    Pneumocephaly
    - ***Beta-2-transferrin +ve in fluid (found exclusively in CSF)
  4. Visual loss
    - ∵ damage to visual pathway
    - close monitoring post-op
  5. ENT symptoms
    - epistaxis
    - anosmia
    - sinusitis
  6. Vascular injury
  7. Intracranial haemorrhage
  8. Mortality (very rare)
22
Q

Pituitary Aploplexy

A

Emergency —> acutely ***↑ ICP
- Acute haemorrhagic infarction +/- SAH

Presentation:
- Headache
- Visual loss
- **Acute pituitary failure (↓ ADH, **Cortisol, T4)
—> Cortisol insufficiency requiring replacement (which can predispose DI ∵ Cortisol ↑ renal perfusion —> further ↓ ADH release —> DI (may need Desmopressin))
—> ***Give Cortisol (most important) before T4 (may predispose Addisonian crisis if hypocortisolaemia not dealt with first ∵ T4 enhance hepatic metabolism of cortisol)

Treatment:
- Urgent surgery for decompression

23
Q
  1. Acoustic neuroma
A
  • **Vestibular schwannoma (arise from nerve sheath of CN8 (vestibular division))
  • at **Cerebellopontine angle —> extend into **Internal acoustic meatus
  • Bilateral in NF2

Presentation:

  1. ***Sensorineural hearing loss
  2. ***Tinnitus
  3. ***Cerebellar dysfunction
  4. Brainstem compression + ***Hydrocephalus
  5. CN5, 7 symptoms (occasionally)

Treatment:
- Surgery / Radiosurgery

24
Q

Summary of Essential knowledge

A
  1. Presentation
    - ↑ ICP symptoms
    - seizure
    - focal deficit (correlate with anatomy)
  2. Pathology
    - age
    - location
    - systemic disease (cancer, NF2)
  3. Imaging
    - location
    - enhancement
    - common DDx
  4. Medical therapy
    - Anticonvulsants (***only for Supratentorial)
    - Steroids
  5. Surgery
    - Indication for resecting metastasis
  6. Use of Radiosurgery
  7. Chemoirradiation for GBM
  8. Treatment principles for Pituitary adenoma + complications of Transsphenoidal surgery

JC WCS (134 decks)

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