Atypical central neurocytoma with sarcomatous differentiation.

We report a case of an intraventricular tumor with features of atypical central neurocytoma with a sarcomatous component in a 44-year-old woman who presented with headaches and vomiting. Magnetic resonance imaging revealed a 3.4-cm lobulated enhancing mass in the occipital horn of the left lateral ventricle, and the patient subsequently underwent a left occipital-parietal craniotomy for debulking. The tumor contained 2 cell populations: round cells with perinuclear halos in a fibrillary background, and spindle cells with oval nuclei arranged in interlacing fascicles with focal necrosis. The round cells had diffuse synaptophysin immunopositivity, while the spindle cells were diffusely immunopositive for vimentin and had intercellular reticulin. The mitotic activity (8 mitotic figures per 10 high-power fields) and the high Ki-67 proliferation index (15.0%) were consistent with atypical central neurocytoma with a sarcomatous component. Although different histologic variants have been described, this is the first reported case, to our knowledge, of central neurocytoma with spindle cell sarcomatous features.