Fig. 1

Radiological and histopathological features of #case 1. a Computed tomography scan showing a large and calcified tumor of the right temporal lobe. b T2-weighted MRI sequence reveals leptomeningeal attachment but no peri-lesional edema. c T1-weighted image, d T1-weighted image after injection of gadolinium showing a heterogeneous enhancement diffusion-weighted images. e Cerebral blood flow was low using arterial spin labeling. f Diffusion was restricted in a large part of the tumor and g apparent diffusion coefficient was low. h Compact tumor with delicate branching vessels exhibiting a chicken-wire pattern mimicking ependymoma (HPS, magnification ×200) with some calcifications (i, HPS, magnification ×200). j Microcyst formation in the tumor (HPS, magnification ×200), k containing occasional neuronal cells (arrowheads, HPS, magnification ×400). l High mitotic index (circles, HPS, magnification ×400) and m elevated MIB1 labeling index (magnification ×400). n Necrosis with calcifications, and microvascular proliferation (arrowheads, HPS, magnification ×200). o Well-circumscribed tumor on neurofilament staining (magnification ×100). p Diffuse expression of Olig2 (magnification ×400) whereas q GFAP was not expressed by tumor cells, with internal positive control (scattered astrocyte remnants designated by arrowheads) (magnification ×400). r NeuN expression by tumor cells (magnification ×400). s Intense EGFR expression (magnification ×400). Black scale bars represent 100 µm (h–j, n), and 50 μm (k–m, p–s) and 250 µm (o). HPS Hematoxylin phloxin saffron