Computed tomography and magnetic resonance features of extraventricular neurocytoma: A study of eight cases

Abstract

To present the neuroradiological and clinical findings of extraventricular (central) neurocytomas (EVNs) to increase awareness of this entity. The computed tomography (CT; n=6), magnetic resonance imaging (MRI; n=8), and clinical presentations of eight patients with pathologically documented EVN were retrospectively analysed. Most tumours were well circumscribed and occurred in young adults. Six tumours were solid or solid-cystic, five of these showed contrast enhancement and three contained calcifications. Multiple small cysts were present in one solid mass and had a "soap bubble" or spongy appearance on MRI. Two other tumours were predominantly cystic; these demonstrated slight contrast enhancement, which contained calcifications. Of the six cases assessed using CT, three showed predominantly hyperdensity and three showed hypodensity, with a mean attenuation value of 75 HU. At MRI, eight masses were isointense (n=4) or hypointense (n=4) to grey matter on T1-weighted images and hyperintense (n=6), isointense (n=1), or hypointense (n=1) on T2-weighted and fluid-attenuated inversion recovery (FLAIR) images. Signal voids were visible in two cases. Four tumours had mild or moderate peritumoural oedema. EVN is a rare neoplasm that can have significant overlap in imaging appearance with other primary brain neoplasms; therefore, it is difficult to make an accurate preoperative diagnosis. However, EVN should be considered in the differential diagnosis when a large cerebral parenchymal mass with cystic change and calcification is encountered in younger patients.