Metastatic disease from primary tumors elsewhere in the body account for approximately 50% of all brain tumors. Metastases to the brain are nearly always via the blood stream. They are typically found at the junctions between the gray and white matter, which are highly vascular. Metastatic lesions commonly present with focal or focal to generalized seizures or slowly progressive neurological deficits. When the lesions become very large, signs and symptoms of increased intracranial pressure develop (i.e., headache, lethargy, nausea and vomiting). The most common primary tumors that metastasize to the brain are lung and breast. Other tumors may also spread to the brain, including melanoma, lymphoma, GI, and GU cancers. In some cases, it is the metastatic lesion in the brain, and not the primary tumor, that brings the patient to medical attention..