Fig. 2From: Clinicopathologic analysis of microscopic tumor extension in glioma for external beam radiotherapy planningPathology slices showing the invasive mode of gliomas of different grades. a LGG. b HGG. The red circles, yellow stars, brown squares, and green triangles represent direct extension, perineural spread, subpial spread, and perivascular spread, respectively. The black line delineates the tumor border, delimited by the naked eye, while the blue line delineates the PTBE border. The purple dotted line delineates the invasive areaBack to article page