Monofocal acute large demyelinating lesion mimicking brain glioma

We report the case of a 34-year-old woman with clinical, neuroradiological and intraoperative histological findings, suggesting a low-grade astrocytic tumour. The demyelinating nature of the lesion was established through biopsy only after neurosurgery. The lesion size, in fact, greatly exceeded that of the perivenous demyelination seen in typical multiple sclerosis (MS) and tended to present as a space-occupying mass. This case underlines the importance of considering demyelinating isolated lesions in the differential diagnosis of a brain mass. Since misdiagnosis can result in unwarranted and aggressive therapy, it is critical for the neurologist to be aware of this serious diagnostic pitfall.