A metastatic brain tumor is brain cancer that has spread from another part of the body.

Many tumor or cancer types can spread to the brain, the most common being lung cancer, breast cancer, melanoma, kidney cancer, bladder cancer, certain sarcomas, testicular and germ cell tumors, and a number of others. Some types of cancers only spread to the brain infrequently, such as colon cancer, or very rarely, such as prostate cancer.

Brain tumors can directly destroy brain cells, or they may indirectly damage cells by producing inflammation, compressing other parts of the brain as the tumor grows, inducing brain swelling, and causing increased pressure within the skull.

Metastatic brain tumors are classified depending on the exact site of the tumor within the brain, type of tissue involved, original location of the tumor, and other factors. Infrequently, a tumor can spread to the brain, yet the original site or location of the tumor is unknown. This is called cancer of unknown primary (CUP) origin.

Metastatic brain tumors occur in about one-fourth of all cancers that metastasize (spread through the body). They are much more common than primary brain tumors. They occur in approximately 10-30% of adult cancers.

• Headache -- recent, persistent, and a new type for the person
• Vomiting -- with or without nausea
• Personality changes
• Emotional instability, rapid emotional changes
• Memory loss, impaired judgment, calculating deficiencies
• Seizures -- new for the person
• Vision changes -- double vision, decreased vision
• Changes in sensation of a body area
• Weakness of a body area
• Speech difficulties
• Decreased coordination, clumsiness, falls
• Fever (sometimes)
• Lethargy
• General ill feeling
• Pupils of eyes are a different size

An examination reveals neurologic changes that are specific to the location of the tumor. Signs of increased pressure within the skull are also common. Some tumors may not show symptoms until they are very large. Then, they suddenly cause rapid decline in the person's neurologic functioning.

The original (primary) tumor may already be known, or it may be discovered after an examination of tumor tissues from the brain indicates that it is a metastatic type of tumor.

• A head CT scan or MRI of the head can confirm the diagnosis of brain tumor and identifies the location of the tumor. MRI is usually more sensitive for finding tumors in the brain.
• Cerebral angiography is occasionally performed. It may show a space-occupying mass, which may or may not be highly vascular (filled with blood vessels).
• A chest x-ray; mammogram ; CT scans of the chest, abdomen and pelvis; and other tests are performed to look for the original site of the tumor.
• An EEG may reveal abnormalities.
• An examination of tissue removed from the tumor during surgery or CT scan-guided biopsy is used to confirm the exact type of tumor. If the primary tumor can be located outside of the brain, the primary tumor is usually biopsied rather than the brain tumor.
• A lumbar puncture (spinal tap) is sometimes also performed to test the cerebral spinal fluid.