Abstract
Extraventricular neurocytoma (EVN) is a rare neoplasm described in the 2007 World Health Organization classification of tumours of the nervous system. Due to the rarity of the tumour, there is limited literature available. The clinical characteristics, pathological features, biological behaviour and outcome of EVN remain unclear, and there are challenges regarding its diagnosis and management. The present case was a 75-year-old man who had been experiencing slow responses to stimuli for 1 month prior to hospital admission. A diagnosis of atypical EVN was made on the basis of pathology and immunohistochemistry results. Atypical pathological features included vascular proliferation, the presence of mitosis and a high MIB-1 (an antibody against Ki-67) labelling index. The disease recurred 7 months after the initial complete resection and radiation treatment, presenting with dural metastasis and codeletion of chromosomes 1p/19q. The present case history and treatment course are discussed with respect to the literature.