Malignant cerebellar ganglioglioma. A case report and review of the literature

Ganglioglioma is usually a well differentiated slowly growing mixed neuronal and glial neoplasm corresponding to WHO grade I or H. However, some gangliogliomas are considered to be WHO grade III because they exhibit anaplastic features in their glial component. Finally there are exceptionally rare cases of newly diagnosed gangliogliomas with grade IV changes in the glial component. We report a case of a 25-year-old woman with a family history of neurofibromatosis who presented initially with a World Health Organization grade IV anaplastic ganglioglioma (a mixed ganglion cell multiform tumor glioblastoma). Despite aggressive management, the patient died of disease in a relatively short period. Histologically, two cell populations were noted: a predominant glial component consisting in a multiform glioblastoma and ganglion cells supporting a diagnosis of ganglioglioma. Immunohistochemical analysis clearly distinguished the two tumor cell populations. Although other cases of grade HI gangliogliomas and twelve cases of grade IV gangliogliomas have been reported, the present case is exceptional in that, to our knowledge, it is the second case of a patient who presented initially with a composite grade IV ganglioglioma and who was clinically followed up to the time of death. This case allows direct comparison between the histological findings in a multiform glioblastoma and a ganglioglioma. It also documents the aggressive biologic behavior of this complex neoplasm.