Intraoperative imprint cytology of central neurocytoma: The great oligodendroglioma mimicker

Intraoperative cytologic evaluation of brain tumors has been used either to render a preliminary interpretation or more often as a complement to frozen section examination. Central neurocytoma is a intraventricular neoplasm, typically located in the region of the foramen of Monro, affecting mostly young to middle age adults. Histologically, central neurocytomas are characterized by monotonous cells with round nuclei and neuronal differentiation within a rich capillary network. Their distinction during intraoperative consultations from oligodendroglioma, ependymoma (mainly clear cell ependymoma), and non-Hodgkin lymphoma can be a diagnostic challenge. We report a case of a 19-year-old female with an intraventricular tumor where imprint cytology preparations were crucial for the intraoperative diagnosis of central neurocytoma. Imprint cytology preparations show a round cell neoplasm associated with neuropil clumps and short straight capillaries admixed with tumor cell clusters. To the best of our knowledge, only a few cases describing the cytologic findings of central neurocytomas have been reported in the medical literature. The differential diagnosis, tissue correlation, clinical-radiologic features, and ancillary studies are discussed.