Huge bilateral pulmonary and pleural metastasis from intracranial meningioma: a case report and review of the literature.

A case of recurrent meningioma with atypical features and extracranial metastases is reported. A 34-year-old female was operated in 1996, 2000, and 2002, and frontal parasagittal meningioma was extirpated. Histological diagnoses of all the resected tumors were meningotheliomatous meningioma, WHO Grade I. However, 2 years later, the tumor recurred in the frontal scalp and was removed again totally. Histological diagnosis was reported as an atypical meningioma; meningotheliomatous type; WHO Grade II. She received radiation therapy. But the tumor had metastasized to the lung and pleura. Transthoracic tru-cut biopsy was performed from large mass of the left lung. Cytopathology was consistent with malignant meningioma, metastasis from the patient's known intracranial meningioma. Ki-67 staining index at the primary and metastatic sites of the present cases were 7 and 5%, respectively. We reviewed and discussed the histopathological features and mechanisms of metastasizing meningioma.