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. 2018 Oct 17;29(1):126–140. doi: 10.1111/bpa.12646

Figure 3.

Figure 3

Pilocytic astrocytoma with anaplasia (PA‐A) with concurrent BRAF duplication, ALT and H3‐K27M mutation (Case 9). This PA‐A developed in the cerebellum of a 53‐year‐old woman during progression from a pre‐existing PA. The precursor and the most recent resection had compact piloid areas with Rosenthal fibers and eosinophilic granular bodies. A. The anaplastic component had brisk mitotic activity B and pseudopallisading necrosis. C. Molecular alterations detected included ultrabright telomere FISH signals indicating ALT D, ATRX loss E, expression of H3‐K27M mutant protein in almost 100% of neoplastic cells F and BRAF duplication G. H3‐K27M expression H and ATRX loss (not shown) were also present in a precursor 2 years prior, although the latter appeared to be present at a lower frequency in neoplastic cells. Next‐generation sequencing detected a AAG‐>ATG missense mutation in H3F3A at codon 27 Lysine K that was changed to Methionine M in all three H3‐K27M immunohistochemistry positive cases tested I.