Cytologic diagnosis of central neurocytoma (CN) in cerebrospinal fluid

―Report of a case―

Abstract

Background : We report a case of CN diagnosed by cerebrospinal fluid cytology.

Case : A 30-year-old female patient seen at this hospital for a blow injury to the head was found on head MRI to have a tumor measuring 43 mm in diameter in the right lateral ventricle. In the intraoperative cerebrospinal fluid cytology preparations, tumor cells were observed in clusters or singly, with pale light green cytoplasm and round nuclei with finely granular chromatin and ill-defined nucleoli, some forming rosettes, a finely fibrillated neuropil matrix. The cells were immunocytochemically positive for synaptophysin. Histologically, the tumor was composed of small round tumor cells in a sheet-like arrangement with fine capillary arcades, some forming Homer Wright-type rosettes. Immunohistochemically, the tumor cells showed positive staining for synaptophysin ; the MIB-1 labeling index was 3%. The histological diagnosis was CN, WHO grade Ⅱ.

Conclusion : In cerebrospinal fluid cytology, use of LBC and immunohistochemical staining, could allow precise diagnosis of CN.