Intracranial meningioma with vertebral or intraspinal metastasis: report of 2 cases and review of the literature.

Extracranial meningioma metastases (EMM) occur in 0.1% of intracranial meningioma patients and are more commonly seen in those with atypical and anaplastic histologies. While the lungs and pleura are the most common site of EMM, intraspinal and vertebral EMM also occur and are not well described in the literature. Although the presence of EMM can worsen prognosis, no standard of care has been established for EMM management. All patients treated for recurrent atypical/anaplastic meningiomas between January 1985 and July 2014 at Memorial Sloan Kettering Cancer Center were screened for intraspinal and vertebral EMM. Of these patients, 2 were identified as having recurrent meningioma complicated by vertebral or intraspinal EMM. A review of the literature was also conducted. The PubMed database was screened for intraspinal and vertebral EMM cases reported in the literature from 1985 to 2015. Nineteen articles were identified from the literature and included 24 individual cases with a total of 34 vertebral or intraspinal EMM. Forty-two percent (10/24) of patients with vertebral or intraspinal EMM had WHO Grade I tumors. Furthermore, 25% (6/24) of vertebral and intraspinal EMM occurred after the primary tumor but prior to any recurrence. This paper highlights that vertebral and intraspinal EMM can occur in patients with WHO Grade I meningiomas and can occur before tumor recurrence. This challenges the notion that EMM are seen primarily in high-grade atypical and anaplastic meningiomas.