Imageandpathologicalobservation: Allimageswere reviewed by two experienced neuroimaging doctors to observe MRI signal characteristics, location, form and size of tumor, boundary peritumoral edema, existence of necrosis, cystic change, haemorrhage and calcification, enhancement degree, mass effect and whether tumor involved ependyma and
pia mater. T1 and T2 signal strength of lesion could be typed into low, slightly low, medium, slightly high and high.
Some authors presume that such meningiomas arise from arachnoid cells of the
pia mater that stretches into the surface of brain or sulcus with perforating blood vessels, while others suggest that the arachnoid cells rest in the brain during the migration progress [3].