Patient went on to have surgery.
Paraffin sections show fragments of a densely hypercellular tumour. Tumour cells show marked nuclear and cellular pleomorphism with scattered cells with xanthomatous foamy cytoplasm noted. There is a diffuse sheeted arrangement of tumour cells. Perivascular cuffs of small lymphocytes are prominent in some areas. A very occasional mitotic figure is identified. No microvascular proliferation is seen and there is no necrosis.
- GFAP positive
- Nestin positive
- NogoA negative
- IDH-1 R132H negative (not mutated)
- ATRX positive (not mutated)
- MGMT negative (likely methylated)
- p53 positive
- p16CDKN2A positive
- Topisomerase labelling index: Approximately 3%
FINAL DIAGNOSIS: Pleomorphic xanthoastrocytoma (WHO Grade II).