Metastasis of breast cancer to intracranial meningioma: case report.

Metastasis of systemic cancer to intracranial tumors is a rare event. The authors report a case of 49-year-old woman with such occurrence, whose breast cancer metastasized to a preexisting parasagittal meningioma at a postoperative interval of 1.5 years. She was admitted to our hospital because of progressive right hemiparesis. Magnetic resonance imaging revealed newly emerged perifocal edema and inhomogeneous contrast enhancement of the meningioma. High choline/creatine ratio and lactate/lipid peak on proton magnetic resonance spectroscopy suggested malignancy. She underwent a tumor resection, and pathologic examination revealed intratumoral metastasis of breast cancer in a transitional meningioma. Immunoreactivity of E-cadherin was detected in both meningioma and breast cancer cells. It is suggested that abrupt appearance of symptoms, inhomogeneous enhancement, and perifocal edema of meningioma is a sign of intratumoral metastasis from systemic cancers.