Cytologic features of central neurocytomas of the brain. A report of three cases

BACKGROUND: Although cytologic smears are major tools for intraoperative diagnosis of intracranial tumors, cytologic features of central neurocytoma, a tumor that has been recognized for only about 15 years, have not been described. CASES: Typical central neurocytomas were encountered in three patients: 40 years old/M, 44/M and 31/F. Intraoperative cytologic smears were reviewed, and all tumors were subsequently examined by conventional histology, immunohistology and, in one case, electron microscopy. The important cytologic appearances were sheets of round cells with finely stippled nuclear chromatin and perinuclear haloes. Calcospherites, neuropil islands and rosettelike structures were focally encountered. The background neuropil was finely fibrillated, but the tumor cells possessed no appreciable cellular processes. CONCLUSION: Central neurocytomas possess distinct cytologic features that help with the intraoperative distinction from oligodendrogliomas and other intraventricular tumors. A combined radiologic and morphologic approach to the diagnosis of this tumor is advised.