Brain metastases represent more than half of intracranial tumors. They are diagnosed in 10% to 30% of adults and 6% to 10% of children with malignant tumors. 98.000 to 170.000 new cases are recorded each year (Johnson et al. 1996) in the United States. In approximately 20% of patients, the brain lesions are the only manifestation of metastatic tumor, while at 80% extracerebral metastases were diagnosed.
Lung cancer, malignant melanoma, breast cancer, renal cell cancer and gastro intestinal cancer are the most common tumor entities, which lead to a brain metastasis.