Editing Human brain (section)

===Tumours===
[[Brain tumor|Brain tumours]] can be either [[benign]] or [[malignant|cancerous]]. Most malignant tumours [[metastasis|arise from another part of the body]], most commonly from the [[lung cancer|lung]], [[breast cancer|breast]] and [[melanoma|skin]].{{sfn|Davidson's|2010|pp=1216-7}} Cancers of brain tissue can also occur, and originate from any tissue in and around the brain. [[Meningioma]], cancer of the meninges around the brain, is more common than cancers of brain tissue.{{sfn|Davidson's|2010|pp=1216-7}} Cancers within the brain may cause symptoms related to their size or position, with symptoms including headache and nausea, or the gradual development of focal symptoms such as gradual difficulty seeing, swallowing, talking, or as a change of mood.{{sfn|Davidson's|2010|pp=1216-7}} Cancers are in general investigated through the use of CT scans and MRI scans. A variety of other tests including blood tests and lumbar puncture may be used to investigate for the cause of the cancer and evaluate the type and [[cancer staging|stage]] of the cancer.{{sfn|Davidson's|2010|pp=1216-7}} The [[corticosteroid]] [[dexamethasone]] is often given to decrease the [[oedema|swelling]] of brain tissue around a tumour. Surgery may be considered, however given the complex nature of many tumours or based on tumour stage or type, [[radiotherapy]] or [[chemotherapy]] may be considered more suitable.{{sfn|Davidson's|2010|pp=1216-7}}