Schilder's myelinoclastic diffuse sclerosis is a rare demyelinating disease, which often mimics intracranial neoplasm or abscess. This disease is of importance to the neurosurgeon in that the clinical manifestations and course may closely simulate brain tumour, including the development of papilloedema and other signs of increased intracranial pressure. We have treated a 29-year-old right-handed young man presenting with left hemiplegia, aphasia and behavioural changes. Magnetic resonance imaging showed two large lesions, irregular contrast-enhancing, in the subcortical white matter of the right frontal and parietal lobes, and increased intracranial pressure. Definitive diagnosis was made with biopsy. The characteristic pathological features are demyelinization of the white matter, lymphocytic perivascular infiltrates, microglial proliferation and immunohistochemical signs. The patient improved with steroid treatment. Schilder's disease constitutes an important diagnosis for any neurosurgeon to be aware of which has not received adequate coverage in the neurosurgical literature.