Fig. 6

Histopathology findings. (HE, LFB-PAS, Bielschowsky, CD3, SV40, Olig2, GFAP, Vimentin, Nogo-A, Ki67, IDH1, p53): a The hematoxylin-eosin (HE) staining revealed grey and white matter with a markedly increased cellularity. Cells appeared pleomorphic and demonstrated a diffuse invasion into the CNS tissue. The tumour cells were embedded into a glial matrix. The nuclei showed a pronounced variation with respect to size and shape and depicted an increased nucleolar prominence. Mitosis was detectable. Signs of necrosis or microvascular proliferation were absent. b The immunohistochemical staining for Glial Fibrillary Acidic Protein (GFAP). Vimentin marked the majority of the tumour cells. c Some of the tumour cells were positive for Olig2. The tumour cells were not positive for NogoA. The proliferation ranged between 2 and 3% as determined by Ki67 immunohistochemistry. d The tumour cells were positive for isocitrate dehydrogenase1 (IDH1) and p53. e, f T-lymphocytes were not increased in the CD3 immunohistochemistry No SV40 positive cells were detected