Atypical Extraventricular Neurocytoma: Imaging Findings of Disregarded Diagnosis.

Extraventricular neurocytoma (EVN) is an exceedingly rare brain tumor. The radiologic and histologic features of EVN are insidious, and only a few reports and clinical cases describe the characteristics of the tumor, which may show different presentations. We report a case of atypical EVN in a 23-year-old man; Computed Tomography and Magnetic Resonance Imaging features of the mass are described, and differential diagnosis are illustrated. In light of the high variability of imaging presentation, the definitive diagnosis of EVN remains histologic. Although some cases have already been reported in the literature, we believe that the description of our case could be useful to increase the knowledge of this insidious tumor, which has gained recognition only over the past 2 decades and should be included in the differential diagnosis in young patients who present brain tumors.