Atypical central neurocytoma: Report of a case

Central neurocytomas are rare, relatively benign intraventricular neoplasms composed of uniform round cells with neuronal differentiation. The majorit y of previously reported central neurocytomas did not recurr after tumor re moval and the patients had favorable postoperative outcomes. Only a few cas es with malignant histopathology or malignant behavior have been noted. Aty pical central neurocytoma is a new entity that was first described in the l iterature in 1997. The tumors have been noted to exhibit a Ki-67 labeling i ndex of 2% or more, or vascular proliferation, mitoses, and necrosis, or bo th. Atypical histologic findings are usually associated with a somewhat les s favorable clinical course and requires postoperative radiotherapy. We rep ort a unique case of a 33-year-ord man with a large intraventricular centra l neurocytoma. The characteristic histopathologic picture, the immunoreacti vity for both synaptophysin and neuron-specific enolase, and the ultrastruc tural features of neuronal differentiation distinguished it from ependymoma and oligodendroglioma. The mitotic activity (up to 3 mitoses/10 high power field) and the high percentage of Ki-67-staining tumor cells (labeling ind ex, 5.0%) in our case were consistant with the atypical variant of central neurocytoma. The patient underwent craniotomy and partial resection of the tumor. Unfortunately, he died of hydrocephalus and brain edema, the next da y.