F-18 FDG-PET imaging of dysembryoplastic neuroepithelial tumor-like astrocytoma.

Cerebral astrocytoma needs to be distinguished from dysembryoplastic neuroepithelial tumor (DNT) when a well-demarcated, cortically based and pseudo-cystic tumor with minimal mass effect is demonstrated on magnetic resonance imaging. We report an unusual case of DNT-like astrocytoma. 18F fluoro-deoxy-glucose (FDG) positron emission tomography showed a focal increase of FDG uptake in a deep part of the tumor. Histologic examination revealed predominantly microcystic change with oligodendrocyte-like cells, leading to a diagnosis of DNT. However, increased cellularity and nuclear atypia of astrocytes within the tumor were conspicuous as for DNT. Four years after excision, tumor recurrence was detected. FDG-positron emission tomography is useful for identifying the malignant potential of DNT-like astrocytoma.