An improved method for generating formalin-fixed, paraffin-embedded cell blocks

Abstract

Cell block preparations of body cavity effusions and washes are more reliable and reproducible than smears, cytospins, and ThinPrep. However, the routine preparation of cell blocks requires a large number of cells within a sample in order to obtain optimal paraffin blocks that contain a sufficient number of embedded cells. The achievement ratio of paraffin-embedded cell block sections from effusion samples has been shown to be 47·7%, which is not optimal for analysis. Therefore, we have developed an improved method called the twice paraffin embedding technique. We modified the current cell block preparation method for effusion samples by adding a ‘cylinder’ to obtain more cell pellets. One hundred and seven effusion and wash fluids samples, which were prospectively obtained from patients, were embedded using this new method. In our study, 82·2% (88/107) of the specimens were successfully embedded into paraffin cell block sections using the twice paraffin embedding technique. The twice paraffin embedding technique is a new, simple, and reliable cell block preparation technique that is suitable for different types of cytology specimens and requires less sample material. We hypothesize that this technique will be widely applicable in the field of cytopathology.