PT  - JOURNAL ARTICLE
AU  - Murase, Makoto
AU  - Tamura, Ryota
AU  - Kuranari, Yuki
AU  - Sato, Mizuto
AU  - Ohara, Kentaro
AU  - Morimoto, Yukina
AU  - Yoshida, Kazunari
AU  - Toda, Masahiro
TI  - Novel histopathological classification of meningiomas based on dural invasion
AID  - 10.1136/jclinpath-2020-206592
DP  - 2021 Apr 01
TA  - Journal of Clinical Pathology
PG  - 238--243
VI  - 74
IP  - 4
4099  - http://jcp.bmj.com/content/74/4/238.short
4100  - http://jcp.bmj.com/content/74/4/238.full
SO  - J Clin Pathol2021 Apr 01; 74
AB  - Aims Histological invasion into the adjacent brain parenchyma is frequently investigated in meningioma because it is an important morphological criterion for grade II meningioma according to the 2016 WHO classification. However, few studies have focused on dural invasion of meningiomas. Herein, we propose a novel histopathological classification based on dural invasion of meningiomas.Methods Forty-nine cases with WHO grade I meningiomas who underwent Simpson grade I removal were collected. After the meningeal layer (ML) and periosteal layer (PL) of dura mater were visualised by Masson’s trichrome stain, we evaluated the depth (to the ML and PL) and the patterns (1, expanding; 2, infiltrating) of dural invasion of meningiomas using serial paraffin sections. Invasion-associated markers, including Ki-67, matrix metalloproteinase (MMP)-1, MMP-9 and MMP-13, aquaporin 1 and Na-K-2Cl cotransporter, were quantitatively analysed by immunohistochemistry.Results Thirty-five cases (71.4%) showed the dural invasion. In 27 of these 35 cases (77.1%), dural invasion was localised in ML. Type 1 (expanding type) and type 2 (infiltrating type) invasions were observed in 23 and 12 cases, respectively. The recurrence rate in cases with type 2 invasion was significantly higher than that in cases with type 1 invasion. The percentage of MMP-1-positive tumour cells was also significantly higher in cases with dural invasion than those without, suggesting involvement of MMP-1 in dural invasion.Conclusions We quantitatively evaluated the depth and patterns of dural invasion in meningiomas. The patterns of dural invasion were associated with meningioma recurrence.