[On diagnostics of malignant meningioma and invasive meningioma]

We have made a clinicopathological study of 90 cases of malignant meningiomas and 18 cases of invasive meningiomas. The results show that the diagnostic features of malignant meningioma include increased cellularity, nuclear pleomorphism, tumorous giant cells, numerous mitotic figures, focal necrosis, cystic change and hemorrhage. The diagnosis of malignant meningioma can be more positively made when invasive growth, recurrence and metastasis are present. In making the diagnosis of invasive meningioma, both changes of benign meningioma and invasive growth should be present.