Fig. 2

Histomolecular features of HGG-MYCN. a Nodules and isolated tumour cells infiltrating the pons parenchyma (Case 2, HPS, × 100 magnification). b Dense proliferation of tumour cells organized in nodules (Case 2, HPS, × 100 magnification). c Hyperchromatic undifferenciated tumour cells presenting, anisocaryotic nuclei with numerous mitoses (Case 2, HPS, × 400 magnification). d highly cellular and undifferenciated proliferation (Case 3, HPS, × 100 magnification). e Hyperchromatic tumour cells presenting anisocaryotic nuclei with numerous apoptotic bodies (Case 3, HPS, × 400 magnification). f Elevated index of proliferation (Case 2, MIB, × 400 magnification). g Preserved nuclear expression of H3K27me3 by tumour cells (Case 3, × 400 magnification). h Lack of expression of Olig2 in tumour cells with positive internal control (residual glial cells) (Case 2, × 400 magnification). i Focal expression of GFAP by tumour cells (Case 2, × 400 magnification). j Expression of CKAE1/AE3 in one case (Case 3, × 400 magnification). k Nuclear accumulation of p53 (Case 2, × 400 magnification). l High-level of MYCN amplification by FISH analysis (Case 4, MYCN locus in green signals and control centromeric in red signals). Black scale bars represent 50 μm, grey scale bars represent 100 μm and the white scale bar represent 5 μm