This is easily apparent on review of contiguous CT and MRI slice images of the lesion. Indeed, there may even be difficulty in finding some subcortical tumors. This problem is more extreme in minimally invasive surgical procedures where surgeons can no longer rely on visualized intracranial landmarks to guide small access ports or endoscopes to the edges of the lesion. A surgeon can get lost attempting to find the tumor.
Brain tissue is damaged unnecessarily.
This can result in neurologic deficit and prolonged and expensive rehabilitation efforts. A surgeon can not tell where tumor ends and normal brain tissue begins. Thus there is some risk that the surgeon can resect normal brain tissue along with the tumor. In important brain areas, this will also result in neurologic deficit. A surgeon performs a subtotal removal of the lesion.