Fig. 5.

Radiological and histopathological features of case #9. Axial T2-weighted and FLAIR image showing a circumscribed lesion of the medulla oblongata (a,b), without enhancement on sagittal T1-weighted image with gadolinium injection (c before injection, d after injection), and low signal on diffusion weighted image (e) with increased diffusion on apparent diffusion coefficient map (f). A paucicellular tumor with subependymal features (g HPS, magnification 400$\times$). No immunoreactivity for Olig2 except in residual glial cells (h HPS, magnification 400$\times$). Neurofilament immunostaining showing an infiltrative pattern (i magnification 400$\times$). Diffuse immunoexpression of H3K27M in tumor cells (j magnification 400$\times$). Scale bars represent 50 µm. HPS: Hematoxylin Phloxin Saffron