Tumor cell distribution in layers of vertical split sections and horizontal cross sections of cell sediments in cell blocks prepared by the test tube method

Objective : In this study, we analyzed the distribution and number of tumor cells (TC) in different sections of the cell sediment prepared by the test tube method (vertical split section (VSS) vs. horizontal cross section (HCS)).Study Design : We prepared nucleated cell sediment layers (VSS and HCS) by the test tube method from 87 pleural fluid samples. We classified the VSS into three layers (A, B, and C) to evaluate the distribution of TC, and counted the TC in the HCS and each layer of the VSS. Based on the findings, we classified the samples into two groups : TC-high (TC-H) and TC-low (TC-L).Results : The 87 samples were classified into 57 TC-H cases and 30 TC-L cases based on examination of the VSS, and into 47 TC-H cases and 40 TC-L cases based on examination of the HCS. In the 57 VSS/TC-H cases, we found uneven distribution of the TC in the three layers in 15 samples. Interestingly, in a proportion of HCS/TC-L cases (9 samples), TC was found only on examination of the VSS, but not on examination of the HCS.Conclusion : Our results showed that examination of VSS specimens prepared by the test tube method might be more useful for evaluating the amount and distribution of TC in a cell block sample.