Intraspinal meningioma with malignant transformation and distant metastasis.

Meningioma is typically considered to be a benign tumor. Malignant transformation and metastasis of meningiomas are rare. Moreover, most meningiomas are intracranial, and there are few reports on intraspinal meningiomas. This report aimed to describe the clinical features and pathological findings of a case of malignant transformation and distant metastasis of intraspinal meningioma, with a review of the literature. A 44-year-old man with a bilateral lower limb paresis was diagnosed with an intradural extramedullary tumor of the thoracic spine. Primary tumor resection was performed, and the histological findings revealed atypical meningioma. The meningioma recurred 2 years after the primary surgery, and a second resection was performed, but only partial resection was possible because of decreased motor evoked potential. At age 48, the patient's lower limb weakness returned, and a third resection was performed, and the histological finding remained atypical meningioma. At age 54, the tumor increased and stereotactic irradiation was performed. At age 60, the patient was diagnosed with metastatic tumors of the rib, lumbar vertebra, cervical spine, and sacrum. Biopsy of the rib metastatic tumor was performed, and the histological findings revealed anaplastic meningioma. This case is the first report of an intraspinal meningioma that transformed from atypical to anaplastic meningioma with distant hematogenous metastasis.