Brain tumours: Glossary of terms

• Meningioma :
  This is a tumour arising from the coverings of the brain rather than the brain itself. Usually, these are benign tumours and if the surgeon is able to remove them in toto they will not recur.

• Pituitary gland :
  This is the controller of the hormonal (endocrine)glands in the body such as the thyroid, adrenal gland and the testes/ovaries. The pituitary gland is situated in a bony recess in the skull base just below the optic nerves as these pass backwards from the orbits (the bony chambers that house the eyes).
  
  Benign adenomas arise from the pituitary gland. Sometimes these over-secrete the hormones that control the endocrine glands in the body. Thus, prolactinoma patients present with amenorrhoea (absent menses) or discharge from nipples, whereas acromegaly patients whose adenomas oersecrete growth hormone present with overgrowth of hands, feet, etc. Many pituitary adenomas do not oversecrete any hormone and present when the tumour grows up to interfere with the visual pathways.

• Neuroma :
  This is a benign tumour growing out from a nerve.

• Craniotomy :
  This refers to the opening of the skull/head at a neurosurgical operation to perform an brain operation.

• Debulking surgery :
  This refers to the operation where the surgeon takes as much tumour out as he can without disturbing/harming the surrounding brain.

• Oedema :
  This refers to the surrounding ‘water-logging’ of brain that inevitably occurs adjacent to high grade primary brain tumours, and often around other tumour types such as metastases.
  
  Many of the neurological problems found at presentation of a brain tumour may be due to defective brain function in the region of the oedema (and not irreversible brain damage) and hence potentially reversible.

• Brain metastases :
  This refers to tumours of the brain that have travelled to the brain from cancer that originated at some other body site. The primary cancers that commonly spread to brain are: lung cancer, breast cancer, kidney cancer, melanoma. Frequently the MR scan shows multiple brain tumours and this suggests to the doctor that he is indeed dealing with metastatic disease.

• Stereotactic radiosurgery :
  This is relatively new technique for obliterating small brain tumours. It is not appropriate for large tumours or those that grow from their edges , such as high grade gliomas but has an ever increasingly important role in the discrete tumours of the meninges, pituitary, acoustic neuromas, some secondary brain disease (possibly replacing surgery for the isolated brain metastasis), angiomas etc