Neurologic dysfunction may result from the following:
Invasion and destruction of brain tissue by the tumor
Direct compression of adjacent tissue by the tumor
Increased intracranial pressure (because the tumor occupies space within the skull)
Bleeding within or outside the tumor
Cerebral edema
Obstruction of dural venous sinuses (especially by bone or extradural metastatic tumors)
Obstruction of CSF drainage (occurring early with 3rd-ventricle or posterior fossa tumors)
Obstruction of CSF absorption (eg, when leukemia or carcinoma involves the meninges)
Obstruction of arterial flow
Rarely, paraneoplastic syndromes (see Paraneoplastic Syndromes)
A malignant tumor can develop new internal blood vessels, which can bleed or become occluded, resulting in necrosis and neurologic dysfunction that mimics stroke.