Malignant Transformation Potential of Dysembryoplastic Neuroepithelial Tumors

Dysembryoplastic neuroepithelial tumor is a relatively recently recognized neuropathological entity that was first proposed in 1988. It is typically considered either a quasi-hamartomatous lesion or a benign, low-grade mixed glioneuronal tumor, and is of World Health Organization grade I classification. Earlier studies suggested the clinical stability of this entity given the predominant lack of regrowth or recurrence on long-term follow-up, even in setting of subtotal resection. However, there is increasing evidence to suggest the possibility of atypical behavior including post-resection recurrence and malignant transformation. Mutagenic effects of adjuvant radiotherapy, subtotal resection, contrast enhancement, and high proliferative activity as reflected by Ki67 labeling index have been postulated as risk factors to malignant transformation. However, ultimately, the rare occurrence, limited descriptions, and conflicting findings in the literature preclude confidently making any meaningful conclusions on this phenomenon.