WHO classification and clinical features of meningiomas

Abstract

Objective To investigate WHO classification,epidemiological law,treatment and prognosis of meningiomas.Methods 791 patients with meningiomas proved by operating and histological examination were retrospectively studied.All the meningiomas were classified as grade Ⅰ,Ⅱ and Ⅲ,based on the current WHO classification.The clinical data of three groups were analyzed.Results Out of 791meningiomas WHO grade Ⅰ made up 93.0％,grade Ⅱ 4.6％ and grade Ⅲ 2.4％.The ratio ( male to female) for WHO grade Ⅰ,]Ⅱand Ⅲ was 1∶2.46,1∶1.77 and 1∶1.11 respectively ( P ＞0.05).The higher risk for WHO grade Ⅰ meningiomas was in an age of 40 ～60 years old,grade Ⅱ 30 ～70,and grade Ⅲ 50 ～ 70.The rates of WHO grade Ⅱ and Ⅲ meningiomas were related to the sites of origin of tumors.The rates of WHO grade Ⅱ and Ⅲ meningiomas at the sites of brain vault and adjacent venous sinuses were higher than those of perisellar region and anterior cranial fossa ( P ＜ 0.05 ).There was no difference between Simpson grades of resection and WHO grade Ⅰ,Ⅱ and Ⅲ meningiomas ( P ＞ 0.05 ).The recurrence rate was 4.8％ for WHO grade Ⅰ meningiomas,versus 38.7％ for grade Ⅱ and 68.8％ for grade Ⅲ ( P ＜ 0.05 ).Conclusions Most of meningiomas are WHO grade Ⅰ.WHO grade Ⅱ and Ⅲ are uncommon.The ratio( male to female) for WHO grade Ⅱ meningiomas is higher than that of grade Ⅰ,and is lower than that of grade Ⅲ.The rates of WHO grade Ⅱ and Ⅲ meningiomas at the sites of brain vault and adjacent venous sinuses are higher than those of perisellar region and anterior cranial fossa.The recurrence after excision correlates with WHO grade. Key words: Meningioma; WHO grade ; Clinical feature; Resection; Prognosis