We report a case of oligoastrocytoma resembling dysembryoplastic
neuroepithelial tumor (
DNT) with malignant transformation. A 35-year-old woman presented with
headache and generalized convulsion in May 2003. Magnetic resonance imaging (MRI) revealed an extensive left temporal lobe
tumor. She underwent partial resection of the
tumor under awake surgery, while preserving her language function. The surgical specimen showed that the majority of the
tumor was composed of a glioneuronal
element. However, there was also an abundant oligoastrocytoma component. Therefore, our first pathological diagnosis was oligoastrocytoma and
DNT. She then underwent
radiation therapy. The
tumor recurred at the left temporal lobe in June 2005. She then underwent open biopsy. The pathological diagnosis was anaplastic oligoastrocytoma with a MIB-1 staining index of 79%. She received PAV (procarvazine,
ACNU, and
vincristine)
chemotherapy, and the
tumor subsided transiently. However, she died 3 years after the first operation. Although the histological findings of the first surgical specimen closely resembled those of
DNT, radiologic findings and
clinical course were different from those of
DNT. The authors concluded that this
tumor could be a malignant transformation of oligoastrocytoma mimicking
DNT, and we wish to give warning that the presence of a glioneuronal component is not an absolute benign hallmark.