MRI classification and imaging findings of dysembryoplastic neuroepithelial tumors

Objective To investigate the MRI classifications and imaging findings of dysembryoplastic neuroepithelial tumor(DNET). Methods MR images of 34 patients with pathologic confirmed DNET of Beijing Sanbo Brain Hospital were retrospectively reviewed in this study. The classification was made according to the number of pseudocysts, scope of involvement, morphology and location. Results MRI appearances of DNET were divided into three subtypes: cystic-like, polycystic-like and diffuse type. Twelve cases had cystic cortical, including front lobe (5 cases), temporal lobe (5 cases), parietal lobe (2 cases). These cases presented quasi-circular or oval shape, with hypointense on T1WI and strongly hyperintense on T2WI. T2-FLAIR was observed hyperintense ring sign in the tumor periphery and the cystic content was close to CSF but having the largest difference to that of CSF, which signal was higher than CSF. Twenty cases were polycystic-like, front lobe (7 cases), temporal lobe (7 cases), parietal lobe (5 cases), occipital lobe (1 case). In these 20 cases, they had slightly hypointense on T1WI and strongly hyperintense on T2WI. Located in the cortex and subcortical matter, with wedge shape, gyriform or triangle shape.On T2-FLAIR, internal septation and hyperintense "ring sign" were observed. Two cases were diffuse type, bilateral (1 case), unilateral (1 case). In these 2 cases, diffuse lesions involving multiple areas with hyperintense ring and internal septation on FLAIR, including subcortical white matter, deep nucleus and periventricular area. Conclusions The MR appearances of DNET are variable. Understanding the MR imaging type of DNET might improve the MR diagnosis of DNET. Key words: Neoplasms, neuroepithelial; Magnetic resonance imaging; Diagnosis