Clinicopathological study of vascular-rich meningeal tumors

Vascular-rich meningeal tumors are usually difficult to remove totally. Some of them have poor prognosis even after the complete removal with radiotherapy, and their histological diagnoses are hard to determine. We operated and followed up 25 cases of vascular-rich meningeal tumors during past 27 years. They were histologically diagnosed by light microscopy using immunohistochemistry and electron microscopy. We present their clinicopathological characteristics. Results: The histological diagnoses were defined by a new WHO classification. They were 12 angiomatous meningiomas (AM), 10 hemangiopericytomas (HP), one mesenchymal chondrosarcoma (MCS), one hemangioendothelioma (HEn) and one malignant fibrous histiocytoma (MFH). Immunohistochemistry of AM showed epithelial membrane antigen (EMA) and connexin positivity, however, that of HP showed no EMA and connexin positive cells. HP showed high Ki-67 staining index. Fine structures of AM exhibited well developed junctional complexes, those of HP showed pericyte-like, fibroblast-like or undifferentiated tumor cells. The tumor size of AM was generally smaller than that of HP. All AM never recurred during 5 to 20 postoperative years. However, all HP recurred and 9 patients died of the disease during one to 9 postoperative years. Radiotherapy was effective in 6 HP, however, all the HP given radiotherapy recurred. One HP given gamma-knife is well 3 years after the second surgery. Histological diagnoses of MCS, HEn and MFH were difficult because of complexity of their histology. One MCS had the vasculature mimicking arteriovenous malformation and bled profusely during the operation. One HEn could be totally removed after radiotherapy and vascular embolization. One MHF was excised after vascular embolization. The patient with MCS died of the metastasis to the lung 6 years after the operation. The case of MFH died of the recurrent tumor 2 years after the first operation. The patient with HEn is doing well 4 years after total removal of the tumor. Conclusion: Vascular-rich meningeal tumors should be totally excised and be followed up precisely by MR image. Their histological diagnoses should be made by using immunohistochemistry and electron microscopy. Radiotherapy including gamma-knife may prevent malignant vascular-rich meningeal tumor from recurrence.