This patient went on to have a trans-callosal resection.
MICROSCOPIC APPEARANCE: The sections show a moderately cellular astrocytic tumour. There are scattered neoplastic astrocytes, with mildly enlarged, hyperchromatic and elongated nuclei. They present as bare nuclei with inconspicuous cytoplasm. No mitoses are seen. There is no evidence of endothelial cell hyperplasia or necrosis. The tumour cells are GFAP positive. The Ki-67 index is 1%. The features are those of diffuse astrocytoma.
FINAL DIAGNOSIS: Right lateral ventricle: Diffuse astrocytoma (WHO Grade II).