RESUMO
We report a case of extraventricular neurocytoma(left parietal lobe) in a young man presented with hemiparesis. The tumor, a radiologically well-circumscribed, cystic and enhancing mass, was partially removed. The patient, who received postoperative radiotherapy, is living well after 15 months of follow-up. Pathology showed a well-differentiated lesion composed of uniform, round cells with perinuclear halos in a neuropil background, immunohistochemically positive for neuronal markers. This was a cystic extraventricular neurocytoma(glio-neuronal tumor) arising from the left parietal lobe. Its features were consistent with neurocytoma pathologically and were different from those of intraventricular neurocytoma pathophysiologically. We outline the morphological and immunohistochemical evaluations necessary to recognize this rare tumor.