Dysembryoplastic neuroepithelial tumor with rapid recurrence of pilocytic astrocytoma component.

Dysembryoplastic neuroepithelial tumor (DNT) rarely has aggressive behavior with recurrence. The authors describe a case of DNT with rapid re-growth and features of pilocytic astrocytoma. A 19-year-old girl presented with a 3-year history of complex partial seizure, which was presumably because of DNT located in the left parietal lobe. The tumor was resected, although a tiny residual lesion with cystic space enlarged with ring enhancement identified on MRI 14 days after surgery resulted in re-excision. The recurrent tumor was eventually proved to be predominantly composed of pilocytic astrocytoma. DNT is known to recur only rarely as a tumor with morphologically different components, and no cases of recurrent DNT with rapidly-growing pilocytic astrocytoma have hitherto been reported in the literature. This phenomenon may be histological "replacement" at recurrence.