Analysis of imaging characteristics of extraventricular neurocytoma

Abstract：Objective To study the CT and MRI features of extraventricular neurocytoma (EVN) of the sellar region and hemisphere, thus to improve the ability of differential diagnosis.Methods Imaging data of 14 patients with pathologically proved EVN were analyzed retrospectively.The patients underwent plain CT, non-enhanced and enhanced MRI.Results Among the 14 cases, there were 5 males and 9 females.5 lesions located in sellar region with range from 4 to 63 years median age: 48 years, and 9 lesions located in cerebral and cerebellar hemispheres with range from 2 to 49 years (median age 19 yrs).Preoperatively, all patients were misdiagnosed as other diseases.EVN of the sellar region were all solid mass and no abnormality in endocrinal exam.The lesions appeared homogenous isodense on CT, slightly hypointense or isointense on T1WI and slightly hyperintense or isointense on T2WI.Calcification (40%), rare cystic necrosis and hemorrhage, and obvious enhancement (100%) were a few distinct imaging characteristics.The extent of enhancement was higher than that of choroid plexus of lateral ventricle.EVN of the hemisphere was all cystic-solid mass in which 55.6% lesions involved frontal lobe.Solid nodule appeared heterogeneous isodense or slightly hyperdense on CT, slightly hypointense or isointense on T1WI, slightly hyperintense or isointense on T2WI.Imaging features included necrosis (66.7%) and calcification (22.2%) of the nodule, fibrous septa in cystic area, and well circumscribed (88.9%) with little to no edema (66.7%).Solid nodule, cystic wall and septations were enhanced.Conclusion Although EVN is a rare neoplasm, it has certain imaging characteristics on CT and MRI.EVN should be considered as a differential diagnosis among patients with solid mass of sellar region in middle aged and elderly patients (especially with normal endocrine exam) and cystic-solid mass of hemisphere in young adults (especially in frontal lobe lesions).