In addition there are some tumors which come from embryologic remnants such as craniopharyngiomas and colloid cysts. Metastatic tumors usually get to the brain by the blood stream. The most common sources are lung cancers, melanoma, renal cell carcinoma, breast cancers and bowel cancers. The presence of a tumor in some brain locations can be irritating and cause the abnormal nerve cell electrical activity which is clinically manifest as seizures. The type of seizure frequently relates to the part of the brain involved by the tumor.
Some brain tumors destroy the brain tissue in which they grow.
The brain functions associated with the involved regions are therefore lost. Tumors at the skull base can damage cranial nerves causing blindness, double vision, loss of facial sensation, hearing loss etc. A growing tumor and swelling which may exist around it increases the contents of this closed box. This will eventually result in an increase of pressure within the intracranial space. This will cause headaches, vomiting, sleepiness and eventually coma and death.