Fig. 3.

Histopathological features in pedHGG-RTK2A/B. a–c Common angiocentric growth pattern of pedHGG-RTK2A and B a, astrocytic differentiation (GFAP expression). b diffuse infiltrating growth is highlighted by an axonal NF staining c. d–i Typical histological characteristics of pedHGG-RTK2A tumors d–i are OLIG2 negativity e, ATRX preservation f, perineuronal satellitosis (g; marked by stars), EGFR expression with angiocentric enhancement h and high Ki-67 index (20%). J–o pedHGG-RTK2B with heterogeneous OLIG2 expression (OLIG2 positive and OLIG2 negative tumor cell populations) k, loss of ARTX l, multinucleated giant cells m, diffuse EGFR positivity n and Ki-67 index of 15%. Scale bars; 20 µm a, g, 60 µm b–f, h–o