Anaplastic ganglioglioma of the cerebellopontine angle. Case report.

A 64-year-old woman presented with a rare anaplastic ganglioglioma in the right cerebellopontine angle manifesting as dizziness persisting for 2 weeks. Preoperative magnetic resonance (MR) imaging revealed a partially enhanced cystic lesion of the right cerebellopontine angle. The tumor was subtotally removed through a right lateral suboccipital craniectomy. The tumor was thought to originate from the brain stem with exophytic growth into the right cerebellopontine angle. Histological examination showed neoplastic ganglional and glial cells with anaplastic features such as mitosis, pleomorphism, and endothelial proliferation. The MIB-1 labeling index of the glial components was 40% to 60%. The diagnosis was anaplastic ganglioglioma (World Health Organization grade IV). She received postoperative radiotherapy but died of respiratory failure with tumor recurrence 11 months after the operation. Gangliogliomas usually have a good prognosis. Histological features of anaplasia and a high MIB-1 labeling index may be predictive of a poor clinical outcome.