Brain tumors

Classification

Primary tumors

  • Gliomas
  • Meningiomas
  • Pituitary tumors
  • Nerve sheath tumors
  • lymphoma

Secondary tumors

  • Local extension
  • Distant metastases

WHO classification of CNS tumors

  1. tumors of neuroepithelial tissue
  2. tumors of cranial and spinal nerves
  3. tumors of meninges
  4. hematopoietic neoplasms
  5. germ cell tumors
  6. cysts and tumor like lesions
  7. tumors of the sellar region
  8. local extension from regional tumors
  9. Metastatic tumors

Tumors of neuroepithelial tissue

  1. Astrocytic tumors
  2. Oligodendroglial tumors
  3. Ependymal tumors
  4. Mixed gliomas
  5. Choroid plexuse tumors
  6. Neuronal tumors
  7. Pineal tumors
  8. Embryonal tumors

General clinical presentation

Supratentorial tumors

  • Headache the most common presentation
  • Progressive focal deficit due to destruction of neural tissues or compression of brain and/or cranial nerves
  • Manifestations of increased ICP
  • Seizures
  • Mental function changes
  • Pituitary dysfunction

Infratentorial tumors

  • Increased ICP
  • Symptoms and signs of mass effect
    • Cerebellar hemisphere: ataxia of the extremities , dysmetria and intention tremors
    • Vermis: truncal ataxia, broad based gait and titubation
    • Brainstem: multiple cranial nerves and long tract signs with vertical nystagmus
    • Tonsillar herniation
  • Focal neurological deficit associated with brain tumors

Frontal lobe:

 Abulia, dementia, personality changes,

Temporal lobe:

Auditory and olfactory hallucinations, memory impairment, contra lateral superior quadrantanopsia

Parietal lobe:

Contra lateral motor or sensory impairment, agnosia, and apraxia homonymus hemianopsia

Occipital lobe:

 Contra lateral visual field defect and alexia

 

Primary brain tumors

Astrocytoma

          Most common primary brain tumor (45-50%)

  • low grade (grades I-II)

          Slowly growing, peak age 40 years, median survival 2-4 years

  • High grade (grades III-IV, glioblastoma multiform)

          Fast growing, peak age 55 years, median survival < 2 years

  • Cystic cerebellar astrocytoma

           Pediatric population, infratentorial potentially curable

Presentation:

Middle aged, recent onset of new, worsening H/A, with vomiting +/– other symptoms

Diagnosis

  • CT brain
  • MRI brain  with contrast

Treatment

  • surgery not curative, aim to improve “quality” life
  • radiotherapy prolongs survival

Meningioma

Mostly benign (1% malignant), slow-growing, non-infiltrative

Presentation:

  • middle aged,
  • symptoms of increased ICP,
  • focal symptoms depend on location

Common locations: parasagittal and falx convexity, sphenoid ridge

Diagnosis:

  • MRI
  • CT with contrast

Curable if complete resection possible (5 year survival > 90%)

 

Vestibular Schwannoma (“Acoustic Neuroma”)

  • Arises from vestibular component of CN VIII at cerebello-pontine angle (CPA)
  • Progressive unilateral deafness = acoustic neuroma until proven otherwise

Presentation: compression of structures in CPA

  • CN V: facial numbness, loss of corneal reflex
  • CN VII: facial weakness (uncommon pre-operatively)
  • CN VIII: unilateral sensorineural deafness, tinnitus, vertigo
  • Cerebellum: ataxia, nystagmus

Diagnosis

  • MRI, CT (contrast enhancing mass in CPA)
  • Audiogram, caloric tests
  • If bilateral: neurofibromatosis type II

 

Management

  • Curable by resection
  • Palliative treatment: gamma-knife radiotherapy

Pituitary Adenomas

Clinical presentation

  • Mass effects
  • H/A
  • bitemporal hemianopsia (compression of optic chiasm)
  • CN III, IV, V1, V2, VI palsy (compression of cavernous sinus)
  • Endocrine effects
  • Hyperprolactinemia
  • Cushing disease
  • Acromegaly
  • Infertility, amenorrhea, galactorrhea, impotence
  • Panhypopituitarism (hypothyroidism)
  • Apoplexy and CSF rhinorrhea (rare presenting signs of pituitary tumor)

Diagnosis:

  • prolactin levels, endocrine function tests;
  • MRI

Differential diagnosis

  • parasellar tumours (e.g. craniopharyngioma, suprasellar
  • (tuberculum sellae meningioma), carotid aneurysm

Management

  • bromocriptine/dopamine agonists for prolactinoma
  • Endocrine replacement therapy
  • Somatostatin analogue (octreotide) +/– bromocriptine for acromegaly
  • Surgery (+/– radiation)

Metastatic Tumors

  • Local extension

          Nasopharynex, maxillary sinus

  • Distant metastases

          Mainly from lung, breast, GIT, kidney, melanoma

Investigation

  • CT brain
  • MRI brain
  • MRI spectroscopy

Management

  • solitary tumor: surgical excision and whole brain radiation
  • Multiple: DXT

 

Principle Treatment of brain tumors

Medical

  • steroids useful for vasogenic cerebral edema (decrease edema around tumors ––> decrease mass effect/ICP)
  • Diuretics
  • Antiepileptic drugs
  • pharmacological treatment for pituitary tumors

Surgery

  • Excision
  • Debulking
  • Biopsy
    • Open
    • Steriotaxic

Radiosurgery

          Gamma Knife

Radiotherapy

Chemotherapy

Gene therapy