The patient went on to have a resection.
The sections show features of a densely cellular astrocytic tumour. The tumour forms sheets and discrete fascicles. The tumour cells have hyperchromatic and pleomorphic nuclei. Some multinucleated tumour giant cells are noted and some have vacuolated (possibly xanthomatous) cytoplasm. Scattered mitotic figures are identified, up to 5 per 10 high-power fields.
Microvascular proliferation is inconspicuous. Scattered small areas of necrosis are present. Tumour cells extend into the cortex. The background also shows many eosinophilic granular bodies and perivascular lymphocytes. The tumour seems to show pleomorphic xanthoastrocytoma-like morphology including fascicular architecture, eosinophilic granular bodies and perivascular lymphocytes. There are no increased reticulin fibres within the tumour.
The tumour cells are p53 positive. Small numbers are synaptophysin and NeuN positive. The Ki-67 index is about 10%. They are CD34, IDH-1 and MGMT immunostains negative.
FINAL DIAGNOSIS: anaplastic pleomorphic xanthoastrocytoma (WHO Grade III).
features images from this case