The sections show a densely calcified, moderately hypercellular glial tumour composed of oligodendroglial and fibrillary astrocytic cells arranged in diffuse sheets. Both components show mild nuclear pleomorphism. No mitotic figures are seen and there is no vascular endothelial cell proliferation and no necrosis. The Ki-67/MIB-1 proliferation index is approximately 3%. The features are of oligoastrocytoma.