Brain Tumor

Diseases,

Neoplastic brain disease can be divided into primary brain neoplasms and metastatic (or secondary) brain neoplasms. Another way of classifying brain tumors is by whether they are intra-axial (within the substance of the brain) or extra-axial lesions. Furthermore, it is useful to note the general and specific locations of the tumor. Brain tumors in adults are more likely to be supratentorial, whereas in children they are usually infratentorial. Specific locations for the brain tumors also narrow the differential diagnosis; for example pituitary region tumors, pineal region tumors, cerebellopontine angle (CP angle) brain tumors and leptomeningeal metastasis all have very different causes.
This section gives a general overview on brain tumors. Other topics in neurooncology include spinal cord tumors and paraneoplastic syndromes
 

Causes of Brain tumours by location:

Extraaxial:

  • Intradural:
    • Meningioma
    • Sarcoma: meningosarcoma, angiosarcoma etc.
    • Metastasis:
      • Lung, breast, prostate, melanoma
  • Extradural:
    • Schwannoma
    • Neurofibroma
    • Metastasis: Subarachnoid seeding a.k.a. Carcinomatous meningitis:
      • Adults: Lymphoma, leukemia, Glioblastoma, breast, lung, GI, melanoma
      • Children: lymphoma, leukemia, Choroid plexus papilloma, ependymoma, PNET, astrocytoma, neuroblastoma

Intraaxial Infratentorial:

Intraaxial Supratentorial Hemispheric:

Pituitary fossa/suprasellar cistern:

Pineal region:

Intraventricular & periventricular region:

Cerebellopontine angle:

 

Primary Brain tumors:

Diagnosis:

Suggested by MRI and confirmed by pathology (brain biopsy/resection)
See individual pages for each type of brain tumor

Investigations to consider:

CT
MRI with & without contrast
Chest X-ray
Catheter angiography: for very vascular tumors like hemangioblastoma or meningioma
CSF analysis: Medulloblastoma & pinealoma can metastasis to the CSF
Stereotactic Biopsy
MRI for operative planning:

  • Image guidance
  • Intraoperative MRI
  • DTI/Tractography
  • fMRI for language and motor function

CT chest, abdomen, pelvis: for primary tumor in suspected metastatic disease
Obsolete tests, historical:

  • Skull X-ray
  • Pituitary view X rays

Treatment:

Treat cerebral edema and Raised intracranial pressure:

  • Dexamethasone (as dexamethasone sodium phosphate): if emergent start with 10mg intravenously. In non emergent cases oral regimen is preferred
  • Consider PCP prophylaxis if on long term steroids

If acute hydrocephalus (noncommunicating or communicating), consider shunting
Consider definitive treatment modalities depending on the tumor:

  • Surgical resection
  • Radiotherapy:
    • External beam: whole brain radatiation therapy, or stereotactic radiosurgery
    • Implanted beeds or wafers
  • Chemotherapy

If Pulmonary embolism or DVT occur, consider:

  • Anticoagulation: heparin, [small retrospective studies]
  • IVC filter [small retrospective studies]

Seizures:

  • Treat only after seizures occur
  • Antiepileptic drugs
  • Treatment of tumor: surgery, radiotherapy

 

 
 

Brain metastasis, a.k.a. secondary brain tumor:

Parenchymal brain metastasis:

Diagnosis:

Suggested by MRI and confirmed by pathology (brain biopsy/resection)

Findings on Investigations parenchymal brain metastasis:

Small, often multiple, at grey-white interface. Well defined. Variable oedema.
CT: hypodense unless hemorrhage, calcification, or hypercellular or hyperproteinaceous.
MRI: T2 oedema is hyperintense, the lesion may be isointense or hyperintense. T1 the lesion is usually hypointense. Enhancing, ring enhancement.

Pathology, in parenchymal brain metastasis:

Histology:

  • Features of primary tumor. Lung, breast, melanoma, renal & GIT cancer.

Immunohistochemsitry may help:

  • AE1/AE3

Treatment of parenchymal brain metastasis:

Options:

  • Surgery, if single metastasis.
  • Radiation therapy
  • Chemotherapy
  • Palliative therapy

Supportive care:

  • Control of seizures, cerebral edema, hydrocphalus and systemic complications such as deep venous thrombosis and pulmonary embolism

 

Leptomeningeal carcinomatosis:

Synonyms:

Leptomeningeal carcinomatosis a.k.a. carcinomatous meningitis a.k.a. neoplastic meningitis, similar to dural metastasis

Diagnosis in leptomeningeal carcinomatosis:

  • Suggested by clinical findings and MRI and confirmed by pathology (biopsy/resection, CSF analysis)

Pathology, meningeal biopsy in leptomeningeal carcinomatosis:

  • Tumor infiltrating the meninges, peripheral nerves, cranial nerves

Clinical features in leptomeningeal carcinomatosis:

Multiple cranial or peripheral neuropathies (polyradiculopathy pattern)
Decreased level of consciousness, encephalopathy, nausea, vomiting (hydrocephalus pattern)

Findings on Investigations in leptomeningeal carcinomatosis:

LP, CSF analysis:

  • 50% positive on 1st tap, 85% on 3rd tap
  • Malignant cells, increased protein, increased cells
  • Low glucose
  • Opening pressure: High with blocked CSF drainage

CT:

  • Communicating hydrocephalus
  • Leptomeningeal deposits (pia, arachnoid),
  • Dural deposists
  • Meningeal enhancement,

MRI:

  • Communicating hydrocephalus
  • Dural metastasis:
    • Dural deposits, T1/T2 variable, FLAIR: hyperintense
    • T1+contrast or FLAIR +contrast: Dural tail enhancement
  • Subarachnoid seeding/Leptomeningeal carcinomatosis:
    • Leptomeningeal deposits (pia, arachnoid) “subarachnoid seeding”, basal cisterns, interpeduncular cistern, cerebellopontine angle cistern, convexities, cranial nerves.
    • FLAIR: hyperintense
    • T1+contrast or FLAIR +contrast: leptomeningeal enhancement, cerebellar or cerebral surface enhancement, nerve root enhancement,

Treatment of leptomeningeal carcinomatosis:

Consider the following options:

  • Intrathecal chemotherapy
  • Radiation therapy
  • Palliative care

Treatment of secondary complications
 

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