What sets brain tumours apart from other tumours that arise within the body?

There are five sets of characteristics which set brain tumours apart

Pic: http://www.medicalartlibrary.com/images/brain-tumor.jpg

from other tumours within the body:

  1. Unlike other types of tumours, the difference between the diagnosis of benign versus malignant brain tumours are not easy to distinguish, and therefore would most likely require an experienced eye to differentiate when examining under the microscope. This may happen because the structural differences of these tumours are quite subtle in nature.
  2. The lethality of brain tumours can be entirely dependent on the location where it is growing rather than the type of tumour: even a benign tumour can be deadly if it is growing in certain locations within the brain.
  3. Brain tumours are notoriously difficult to remove due to both the presence of the skull and the chance of brain damage occurring if normal tissue is interfered with when the tumour is removed
  4. Most brain tumours remain relatively localized within the brain itself rather than metastasize; their only route of escape to other parts of the body is through the subarachnoid space within the meninges.
  5. Even when the tumours are benign or low-grade (slow in growth and well-differentiated), they can still have a poor prognosis: usually, tumours of this style in other parts of the body are able to be excised and have a good prognosis or even a chance of cure.

What are the types of brain tumours? 

Pic: http://atlasgeneticsoncology.org/Tumors/Images/MeninMacro.jpg

There are several types of brain tumours. There is one major category of brain tumours and they are known as gliomas. Gliomas are defined as tumours of glial cells. There are three types of gliomas:

  • Astrocytomas, (Glioblastomas are within this category)
  • Oligodendrogliomas
  • Ependymomas.

Other types of brain tumours include: neuronal tumours, poorly differentiated neoplasms, CNS lymphomas, germ cell tumours, meningiomas and metastatic tumours. The tumours may also present with paraneoplastic syndromes.

What are paraneoplastic syndromes?

Paraneoplastic syndromes are symptoms that arise not because of the tumour itself, but because of either an immune response against the tumour or because of humoral (B cell-related) factors such as hormones or cytokines. Age is a key factor in determining whether a person develops paraneoplastic syndromes along with a tumour: it tends to happen more often in people that are middle aged or elderly. They can happen in several tissues within the body, but it is most detrimental if it occurs within the central nervous system. The symptoms of paraneoplastic neurological syndromes are fairly rare, but they can occur even before the cancer is diagnosed. The symptoms include:

  • Dizziness
  • Difficulties in swallowing
  • Ataxia (difficulties in maintaining balance)
  • Lack of muscle tone
  • Dementia (loss of memory)
  • Seizures
  • Loss of fine motor movements
  • Slurriness in speech without being intoxicated/drunk
  • Nystagmus (loss of ability to control movement in the eyes)