metas brain tumors

METASTATIC BRAIN TUMORS 601 CHAPTER 28 Metastatic brain tumors Lisa M. DeAngelis, MD, Jay S. Loeffler, MD, and Adam N. Mamelak, MD Brain metastases occur in ~15% of cancer patients as a result of hematogenous dissemination of systemic cancer, and the incidence may be rising with better control of systemic disease. Lung and breast cancers are the most common solid tumors that metastasize to the CNS. Melanoma and testicular and renal carcinoma have the greatest propensity to metastasize to the brain, but their relative rarity explains the low incidence of these neoplasms in large series of patients with brain metastases. Patients with brain metastases from nonpulmonary primaries have a 70% incidence of lung metastases. Although many physicians presume that all brain metastases are multiple, in fact, half are single and many are potentially amenable to focal therapies. Signs and symptoms Lateralizing signs and symptoms of brain metastasis depend on the location of the lesion(s) and are similar to the signs and symptoms of other space-occupying masses. However, a few features unique to brain metastases deserve emphasis. Seizures Focal or generalized seizures are the presenting symptom in 15%-20% of patients with brain metastasis. Metastases from melanoma have a 50% inci- dence of seizures, perhaps due to their hemorrhagic nature. Lateralizing signs More than half of patients with brain metastases have later- alizing signs, including hemiparesis, aphasia, or visual field deficits. Headaches are seen in about half of patients but are rarely an isolated finding of metastatic disease. Altered mental status Approximately 75% of patients with brain metastases have impairment of consciousness or cognitive function. Some patients with multiple bilateral brain metastases may present with an altered sensorium as the only manifestation of metastatic disease; this finding can be easily confused with a metabolic encephalopathy. METASTATIC BRAIN