Inter-Observer Variation in the Grading of Meningiomas using the WHO Classification of CNS Tumors Criteria
Background: Grading of meningiomas using the World health organization (WHO) Classification of the Central Nervous System criteria currently has an essential role in classification, treatment, prognosis prediction, and research of these tumors. Aims: This is a retrospective study that assessed the interobserver variation between Anatomical Pathologists in grading meningiomas using material obtained from ten resection specimens. The WHO grading system includes different methods, including the mitotic count, the tumor subtypes or the presence of three out of five certain morphological features. This paper focuses on the interobserver variability in the latter method. Methods: Meningiomas that were originally graded based upon mitoses, brain invasion, or morphological subtype were excluded. Ten different Anatomical Pathologists, including two Neuropathologists, who were blinded to the original diagnosis and grade graded the tumors independently.
