Sections show multiple fragments of glial tissue which has a cellular neoplasm. The tumour consists of round cells with round nuclei with stippled chromatin pattern. The tumour cells have a moderate amount of granular eosinophilic cytoplasm with some perinuclear clearing. There is a background delicate vascular structure with calcifications present. The figures are not conspicuous. No endovascular proliferation or necrosis is seen.
IMMUNOHISTOCHEMISTRY:
- Olig-2: Positive
- IDH-1 R132H: Positive (mutated)
- ATRX: Intact (non-mutated)
- p53: Positive (unusual in oligodendrogliomas, but reported)
- ki67: 60%
1p19q co-deletion confirmed by FISH.
FINAL DIAGNOSIS
oligodendroglioma, IDH-mutant, and 1p/19q-codeleted (grade 3)