Necrosis is a consistent factor to recurrence of meningiomas: should it be a stand-alone grading criterion for grade II meningioma?

The purpose of this study was to evaluate spontaneous necrosis as a possible isolated factor for progression and recurrence in grade I meningiomas classified according to the current World Health Organization (WHO) classification. Meningiomas are the most frequently reported primary intracranial tumours, accounting for more than 35%. The 2016 WHO classification of central nervous system tumors stratifies meningiomas in grades I (benign), II (atypical), and III (malignant), according to histopathological aspects and the risk of progression or recurrence. Among 110 patients with intracranial meningiomas, 70 were WHO grade I meningiomas with no findings of atypia (G1WON), 15 were WHO grade I with necrosis (G1WN), 21 were WHO grade II (G2), and 4 were WHO grade III (G3). The mean follow-up was 5.9 ± 0.2 years. High performance scale (KPS ≥ 80) was different (p