Combined "Infiltrating Astrocytoma/Pleomorphic Xanthoastrocytoma" Harboring IDH1 R132H and BRAF V600E Mutations.

摘要: Pleomorphic xanthoastrocytoma (PXA) has rarely been reported in combination with infiltrating glioma, historically interpreted as a "collision tumor." Isocitrate dehydrogenase 1 (IDH1) and BRAF V600E mutations are usually not concurrent. The former is typical of adult gliomas, the latter identified variety primary central nervous system neoplasms, including PXA, ganglioglioma, pilocytic astrocytoma, gliomas. We report case 56-year-old man presenting seizures headaches. Magnetic resonance imaging revealed large right temporal lobe mass low T1 high T2/FLAIR signal discrete contrast-enhancing focus. Histologically, tumor showed 2 distinct components: an astrocytoma harboring 5 mitoses/10 high-power fields relatively circumscribed focus, resembling PXA with, at most, fields. No microvascular proliferation or necrosis was present either component. component contained numerous axons, whereas PXA-like had sparse demonstrated by neurofilament immunostain. Both components were positive for mutant IDH1 R132H loss ATRX expression, restricted to On sequencing separately after microdissection, both identical TP53 R273C point mutations, mutation limited These findings consistent clonal expansion morphologically private within IDH1-mutant glioma. Intratumoral heterogeneity evolution, seems have occurred here, suggest reevaluation tumors" concept.