A hypertensive patient who had been treated successfully for normal pressure hydrocephalus (NPH), died from a left thalamic haemorrhage. Neuropathological examination showed recent and old thalamic haematomas and numerous parenchymal cavities or 'cerebral lacunae'. Two lacunae bulged into the lateral ventricles, and had all the characteristics of so called 'expanding lacunae'. They were surrounded by a single layer of epithelial-like cells, contained a normal, patent, arteriole, and presented as space occupying lesions. Only two similar cases have been reported previously. The complexity of the neuropathological features of 'cerebral lacunae' is emphasized and the relationships between cerebral hypertensive disease, NPH, and expanding lacunae are discussed.