Türk Nöroşirürji Dergisi 2011 , Vol 21 , Num 2
Atypical and Malignant Meningiomas
Melike MUT
Hacettepe Üniversitesi, Tıp Fakültesi, Nöroşirürji Anabilim Dalı, Ankara Meningiomas are the most common tumors of the central nervous system. Atypical meningiomas (World Health Organization Grade II) have been recognized more frequently after objective diagnostic criteria of the 2000/2007 WHO tumor grading system. Atypical meningiomas constitute approximately one fourth of all meningiomas. The presenting symptoms may change according to tumor location, size, growth rate and mass effect to the surrounding tissues. They are difficult to differentiate from benign meningiomas with preoperative imaging studies. Even Simpson grade I resection may not suffice for tumor control with a 41% recurrence rate at 5 years. Recurrent disease also shortens overall survival. It is not clear whether postoperative radiotherapy should be given after the resection of atypical meningiomas.

Malignant meningiomas constitute 1-3% of all meningomas and they are WHO Grade III tumors with certain diagnostic criteria. This group also includes the papillary and rhabdoid subtypes. They are locally aggressive and invasive tumors and rarely metastatic. Preoperative imaging studies may not differentiate them from the other meningiomas. There is no consensus for the therapeutic approaches to these rare tumors although maximum resection followed by the radiotherapy is mostly employed. Anahtar Kelimeler : Atypical, Malignant, Meningioma, Simpson resection grade