Angiocentric glioma with high proliferative index: case report and review of the literature.

With less than 50 cases previously reported in literature, angiocentric glioma (AG) is an uncommon, slow-growing tumor of the CNS that typically exhibits a low proliferative rate and is generally surgically curable. We report the case of a 3-year-old child who presented with seizures and was found to have a non-enhancing parietal lobe lesion with overlying calvarial remodeling. Following complete resection of the tumor, histopathological examination revealed bipolar spindle cells centered on cortical blood vessels, forming pseudorosettes with an ependymomatous appearance. Tumor cells were glial fibrillary acidic protein (GFAP) positive, yet failed to label with synaptophysin. Scattered tumor cells had a "dot-like" cytoplasmic staining with the antibody against epithelial membrane antigen (EMA). Collectively, these features favored a diagnosis of AG. Interestingly, the monoclonal antibody against Ki-67 (MIB-1) labeling rate averaged approximately 10.0%. The child continues to be tumor- and seizure-free ten months postoperatively. Long-term follow up is required to determine if the high proliferative rate observed in this AG translates into altered clinical behavior and/or a worse prognosis.