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Washington University Experience | NEOPLASMS (GLIAL) | Astrocytoma, IDH-mutant, WHO Grade 4 | 9A4 IDHmut Astro Gr4 (Case 9) H&E 20X
This is a diffuse glioma with variably increased cellularity. Many tumor cells have small, hyperchromatic, atypical nuclei and moderate eosinophilic cytoplasm. The other subset of tumor cells have eccentric nuclei with abundant eosinophilic gemistocytic cytoplasm. There is moderate to marked pleomorphism with few multinucleated and bizarre tumor cells. Mitoses are easily identified, and microvascular proliferation is multifocal. ---- Not shown: Immunohistochemical stains show reactivity for IDH1 (p. R132H) in the tumor cells. Nuclear reactivity for ATRX is lost in most of the tumor cells. Reactivity for p53 is present in a substantial subset of tumor cells. Ki-67 labeling index is increased, focally reaching up to 12.6%. ---- FISH studies reveal loss of PTEN and polysomy of chromosome 7. No EGFR amplification was identified. ---- Comment: The collective features are consistent with an integrated diagnosis of IDH (R132H)-mutant astrocytoma, WHO grade IV. Molecular studies at Foundation One, genomic alterations were identified in IDH1, ATRX, TP53 mutations and CDKN2A/B loss.
