Filter paper-assisted cell transfer (FaCT) technique: A novel cell-sampling technique for intraoperative diagnosis of central nervous system tumors.

Abstract

Intraoperative diagnosis of central nervous system (CNS) tumors provides critical guidance to surgeons in the determination of surgical resection margins and treatment. The techniques and preparations used for the intraoperative diagnosis of CNS tumors include frozen sectioning and cytologic methods (squash smear and touch imprint). Cytologic specimens, which do not have freezing artifacts, are important as an adjuvant tool to frozen sections. However, if the amount of submitted tissue samples is limited, then it is difficult to prepare both frozen sections and squash smears or touch imprint specimens from a single sample at the same time. Therefore, the objective of this study was to derive cells directly from filter paper on which tumor samples are placed. The authors established the filter paper-assisted cell transfer (FaCT) smear technique, in which tumor cells are transferred onto a glass slide directly from the filter paper sample spot after the biopsy is removed. Cell yields and diagnostic accuracy of the FaCT smears were assessed in 40 CNS tumors. FaCT smears had ample cell numbers and well preserved cell morphology sufficient for cytologic diagnosis, even if the submitted tissues were minimal. The overall diagnostic concordance rates between frozen sections and FaCT smears were 90% and 87.5%, respectively (no significant differences). When combining FaCT smears with frozen sections, the diagnostic concordance rate rose to 92.5%. The current results suggest that the FaCT smear technique is a simple and effective processing method that has significant value for intraoperative diagnosis of CNS tumors. Cancer Cytopathol 2017;125:277-282. © 2016 American Cancer Society.