Clinicopathological features, imaging characteristics and surgical management in a novel tumour entity - aggressive meningiomas

Meningiomas are common neoplasms of the central nervous system, comprising between 24 and 30% of primary intracranial tumours, most commonly affecting females in their middle age or later adult life [1] [2]. Meningiomas are classified as benign, atypical or anaplastic meningiomas depending mostly on histopathological criteria known to be associated with worse prognosis in terms of tumour progression, recurrence risk after surgery and overall survival. The 2016 edition of the World Health Organization (WHO) classification of Central Nervous System (CNS) tumours recognizes brain invasion as an independent criterion for diagnosing an atypical grade II meningioma [3]. Meningioma grading based on the WHO classification of CNS tumours thoroughly impacts therapeutic management and tumour prognosis. Aggressive meningiomas, a different phenotype of tumours, characterized by rapid growth and involvement of adjacent brain tissue, blood vessels and bone, was not previously listed as an independent entity in the WHO classification of meningothelial-cell tumours.  Regarding the increasing importance of tumour grading in meningioma treatment strategies, the authors here provide an overview of clinicopathological and radiographic features, surgical management and long-term prognosis of this novel meningothelial tumour entity, the aggressive meningioma. In particular, we aimed to describe pre-, intra- and postoperative methods for recognizing aggressive meningiomas and explore the implications of this diagnosis on both surgical strategies and adjuvant therapy.