The leptomeninges were fibrotic with increased vascularity and patchy chronic inflammation, predominantly T cells. The cortex displayed prominent reactive gliosis, microglial activation with multifocal microvascular proliferation, mild neuronal loss, demyelination with partial axon preservation, sparse T cells (predominantly CD8+), and some haemosiderin deposition. There were scattered dysmorphic neurons, some with enlarged nuclei, marginated chromatin, and peripherally displaced Nissl substance, and several bizarre astrocytes with enlarged hyperchromatic pleomorphic nuclei.