Meningeal hemangiopericytoma with delayed multiple distant metastases.

A 43-year-old housewife suffered from an occipital headache, and brain computed tomography (CT) showed an occipital meningeal tumor. She received a complete tumor excision and the tumor pathology was interpreted as atypical meningioma. Five years later, a subacute left neck pain with radiation to the left arm occurred. A tumor invading the second and third cervical vertebrae with compression on the dural sac was found. Angiography revealed hypervascular tumor staining supplied from the left vertebral artery. CT-guided biopsy was performed and nests of atypical spindle cells accompanied by staghorn vascular pattern were revealed histologically. Immunohistochemical studies showed positive vimentin staining but negative reactions to epithelial membrane antigen, cytokeratin low molecular weight, cytokeratin high molecular weight, CD34 and S-100 protein. Estimation of the Ki-67 proliferative (mitotic) index by using MIB-1 monoclonal antibody was 12%. Later on, a systemic survey revealed lesions in the left lung, liver and kidney. The diagnosis was revised to hemangiopericytoma. Distant metastasis is common in this tumor. However, the delayed multiple metastases without local recurrence were relatively rare. The clinical course in this patient also supported that a high mitotic activity may correlate with a poor prognosis even if the pathology is taken from the metastatic tissue, and that long-term follow-up is mandatory. Detailed immunohistochemical staining is helpful in avoiding misdiagnosis of meningioma.