Metastatic meningiomas: an unusual clinical and pathological diagnosis with highly variable outcome.

Metastatic meningioma is a rare situation. We conducted a retrospective study from our databases and identified cases of metastatic meningioma. We report three presentations of patients with medical history of surgical removal of meningioma presenting several years later a liver tumor with bone metastasis or multiple lung tumors. These observations highlight the difficulty of the clinical and pathological diagnosis and the absence of consideration of metastatic state for histologically "benign" but clinically aggressive meningiomas in the current WHO 2007 classification of meningiomas. We also reviewed published cases of metastatic meningiomas since they are clearly distinguished from haemangiopericytoma.