PLOW CYTOMETRY - IN-VITRO ASSESSMENT OF ITS POTENTIAL APPLICATION FORDIAGNOSIS AND CLASSIFICATION OF LYMPHOID PROCESSES IN CYTOLOGIC PREPARATIONS FROM FINE-NEEDLE ASPIRATES

Detection and accurate classification of lymphoid processes in fine-ne edle aspirate specimens can be a challenging task for the pathologist. Recognizing the usefulness of flow cytometric methods for the diagnos is of lymphoproliferative disorders (LPDs), the authors applied flow c ytometric analysis to 38 tissue samples that had a possible diagnosis of LPD and to fine-needle aspiration-derived cytologic preparations. F our aspirations from each sample provided from .44 x 10(6) to more tha n 70 X 10(6) cells in total. The highest yields were associated with l ow-grade B-cell non-Hodgkin's lymphomas (NHLs). Washing cytologic prep aration cell suspensions did not enhance diagnostic ability and dramat ically reduced cell counts (average decrease, 79.8%), potentially prob lematic with small samples. Comparison of ploidy, S fraction, and immu nophenotypic data from the cytologic preparations and cell suspensions made from the conventionally processed parent tissues indicates that cytologic preparation composition closely parallels the tissue of orig in. A multiparametric flow cytometric technique used to enhance detect ion of B-cell clonal expansions allowed for successful recognition of 17 of 21 (81%) B-cell NHLs in cytologic preparations, with false-negat ive results primarily reflecting a lack of viable tumor cells in the c ytologic preparation cell suspensions. A T-cell NHL and a nonhematopoi etic malignancy were also identified in cytologic preparations. None o f the benign conditions were interpreted as lymphoma. Flow cytometric techniques applied to fine-needle aspirates of lymphoid processes yiel d important diagnostic information, which may be maximized by adaptati ons in processing and flow cytometric analysis.