MKI67 and meningioma: By assessing PSMA endothelial staining in meningiomas grades 1–3, we aimed to demonstrate the variability of PSMA expression in meningiomas in the context of WHO-defined atypical features (including brain invasion, mitoses, presence of necrosis, hypercellularity, small-cell change, macronucleoli, and sheeting architecture), and the Ki-67 proliferation index.