The usefulness of MR imaging in the diagnosis of dysembryoplastic neuroepithelial tumor in children: a study of 14 cases

Abstract

Background and purpose: Dysembryoplastic neuroepithelial tumors (DNTs) are benign lesions affecting children and are associated with epilepsy. The goal of our study was to better characterize the clinical-radiologic-pathologic spectrum of DNTs (complex and simple forms only) in a series of 14 children.

Methods: Clinical, neuroradiologic, and pathologic features of all cases were retrospectively studied.

Results: Eleven cases of complex and three cases of simple DNTs were identified. Mean follow-up was 87 months, and no recurrence was recorded except for one case of simple DNT. We found that some neuroradiologic features may be helpful to support the diagnosis of DNT: presence of "septations," triangular pattern of distribution, and absence of contrast enhancement.

Conclusion: The evidence of the specific glioneuronal element is found by pathologic examination, but the typical neuroradiologic aspect of DNT suggests this diagnosis preoperatively. Radiologic examination may be helpful for the diagnosis of DNT when pathologic findings are inconclusive.

Fig 1.

Typical DNT findings. A, Sagittal T1-weighted MR image shows a large lesion of low signal intensity involving the temporal lobe, without edema or mass effect and corresponding to a complex form of DNT. The lesion is divided by septations leading to an alveolar aspect. B, The lesion is of high signal intensity on this T2-weighted MR image. The septations appear to be of low signal intensity. C, Sagittal T1-weighted MR image shows a frontoparietal DNT with sharp boundaries and a rectangular pattern of distribution. D, Coronal T2-weighted MR image illustrates the triangular pattern of distribution typical of DNT, with a tumor width that is maximal at the cortical level and decreases toward brain ventricles. E, Low-magnification view showing the cortical location and the nodular architecture typical of DNT (hematoxylin phloxin-saffron, magnification ×10). F, The glio-neuronal specific element is composed of oligodendrocyte-like cells surrounding areas of mucoid substance containing “floating neurons” (hematoxylin phloxin-saffron, magnification ×300).

Fig 2.

DNT involving the occipital lobe and presenting hemorrhagic changes (case 7). A, On CT scan, the lesion appears of low attenuation and shows a nodular enhancement after contrast injection. B and C, On transverse (B) and sagittal (C) T1-weighted MR images, the DNT is of low signal intensity, displays septations, but shows three areas of hyperintensity after gadolinium injection, mimicking a glioma. D, Transverse T2-weighted MR image shows the absence of edema and mass effect on median structure. E, Marked nuclear atypias can be observed in the glial areas of DNT (hematoxylin phloxin-saffron, magnification ×200). F, An oligodendroglioma-like area showing major hemorrhagic changes characterized by numerous hemosiderin-laden histiocytes (hematoxylin phloxin-saffron, magnification ×200).