Atypical characteristics and behavior of dysembryoplastic neuroepithelial tumors

Dysembryoplastic neuroepithelial tumors (DNET) are classically considered as benign, cortically based tumors that are stable. However, there were case reports that suggested DNET may not be as benign as previously thought. The purpose of our study was to identify atypical location, characteristics, and behavior of DNET in children.

The MRI images of 51 patients with pathologically proven DNET were retrospectively reviewed. The following were assessed: tumor location, neuroimaging appearances including hemorrhage, calcification and edema, tumor growth preoperatively and after subtotal resection, tumor recurrence, malignant transformation, and metastatic seeding.

Two (3.9 %) patients had intraventricular lesions, three (5.9 %) had associated edema, three (5.9 %) had calcifications, and one (2 %) had hemorrhage on preoperative CT and MRI. Sixteen of 51 (31.4 %) lesions exhibited enhancement post gadolinium administration. Six of 29 (20.7 %) preoperative lesions that had follow-up imaging were enlarging prior to surgery. In 6 of 18 (33.3 %) with subtotal resection, there was an increase in size of the residual tumor. Tumor recurrence at the surgical bed occurred in 3 of 30 (10 %) patients who had gross total resection. Two of 51 (3.9 %) cases developed secondary lesions distant to the primary tumor; the secondary lesions were within the lateral ventricles.

In children, DNET may have atypical location, characteristics and behavior, including growth of primary or residual lesions and multifocal tumor. These findings emphasize the need for follow-up of patients with DNET post-resection.