Pathology
H&E
MICROSCOPIC DESCRIPTION: Paraffin sections show a densely cellular glial tumour. Tumour cells have oligodendroglial morphological features - round and oval nuclei with vesicular chromatin and perinuclear clearing with tumour cells arranged in lobules delimited by thin-walled capillaries. A very occasional mitotic figure is identified. There is no multilayering of atypical cells around vessel Iumena and no necrosis is identified. There is patchy tumour calcification. Tumour extends through the full thickness of cerebral cortex, breaches the pia-arachnoid and extends into the sub-arachnoid space.
IMMUNOHISTOCHEMISTRY:
GFAP negative in tumour cells NogoA positive IDH-1 R132H positive (mutated) ATRX positive (not mutated) P53 positive P16 CDK NZA positive Topoisomerase labelling index: Approximately 10%
FISH for chromosome 1p/19q deletion:
- Chromosome 1. Mean copies 1p per cell: 1.40 Mean copies 1q per cell: 2.17 1p/1q ratio: 0.65 Interpretation: 1p loss detected by FISH
- Chromosome 19 Mean copies 19q per cell: 1.13 Mean copies 19p per cell: 1.88 19q/19p ratio: 0.60 Interpretation: 19q loss detected by FISH
FINAL DIAGNOSIS: Oligodendroglioma (WHO Grade II)