Histopathologic classification of meningiomas and the prognostic importance of morphology in meningiomas

The aim of histomorphological examination in surgical pathology is prescience of tumour?s biological behaviour. Diagnosis, differential diagnosis and grading criterions are propounded for this aim and tumours are classified based on these matters. Actual examination in practical surgical pathology must be done based on these classifications. Although reliance of true aggreement occurs in time, every classification system must be revised with new findings and informations after a time. In this study, a retrospective investigation from archieve materials was done and value of findings in and out of the actual grading system were questioned according to Tumours of Central Nervous System World Health Organization (WHO) 2007 Classification. This study was analysis of characteristics of 455 meningioma cases operated in Gazi University Medicine Faculty from 2006 to 2012. They were reclassified according to World Health Organization (WHO) 2007 Classification and evaluated clinically and morphologically. Mean age of patients with meningiomas was 50,84 + 13,627. The female: male ratio of 455 cases was 2,6:1. Intracranial (%57,1) and supratentorial (%74,3) located meningiomas were the most common. The frequency of grade 2-3 and grade 1 meningiomas was %30,8 (n:140), %69,2 (n:315) respectively. The most common variants were meningothelial (%34,9), grade 2-3 (%23,8) and transitional (%17,1). The ratio between grade 2-3 meningiomas and grade 1 meningiomas was 0,4. According to comparison of World Health Organization (WHO) 2000 and 2007 Classifications grade 1 meningiomas decreased %7,1, grade 2 and grade 3 meningiomas increased %6,4 and %0,7 respectively. %17,1 of all patients have neural tissue invasion and %3,1 (n:14) of all patients have clinically recurrence. 35 (%7,7) cases are upgraded from the original grade without recurrence according to World Health Organization (WHO) 2007 Classification. Cases upgraded without recurrence and brain invasion are upgraded because of mitosis and papillary pattern. Mitosis is the only basic arbiter in grading and must be evaluated apartly from other parameters. Ki-67 (because of ratio, not number) is also very important for mitotic evaluation. Histomorphologically, it was thought that cellularity and patternless pattern can be the morphological viewpoint of the same finding. Although cytologic atypia is not a criterion in the literature, it was concluded that diffuse cytologic atypia can be included in grading out of mitosis. As in conclusion part defined, it was attracted attention that criterions out of actual grading can have place in actual grading based on findings out of mitosis and criterions of actual grading can also have not the same value in actual grading. After this point, new alternative grading schema should be created and from this time this new grading schema also should be prospectively used for diagnosed cases with World Health Organization (WHO) 2007 Classification. After reaching large case series, comparison between these used and rigueur grading schemas should be appropriate for utility.