Figure 4

Immunohistochemical staining of lesion. Immunohistochemical staining for EMA demostrated the neoplastic cells were focally positive in atypical meningioma area (a), but lack of immunoreactivity in the spindle cells of meningioangiomatosis area (b). Higher cellular proliferation was observed in the atypical meningioma area with approximately 20% of MIB-1 index (c), but lower MIB-1 index of up to 1% was detected in the spindle cells of meningioangiomatosis area (d). (a-d, immunohistochemical staining with original magnification of 400×)