Flow cytometric immunophenotyping in fine-needle aspiration of lymph nodes

Fine-needle aspiration (FNA) of lymph nodes has been regarded as a useful method in the diagnosis of lymphadenopathy. However, this procedure has been shown to be of limited value in the diagnosis of low or intermediate grade malignant lymphomas in some studies. Immunophenotyping is an essential adjunct to cytomorphology for the diagnosis of lymphoma by FNA. Immunophenotyping using flow cytometry (FCM) is rapid, objective and reliable. Using FCM, multiparametric analysis of 33 FNA materials from lymph nodes was performed and profiles of surface markers of lymphoid cells were assessed. In reactive hyperplasia, patterns of cell surface markers were quite variable, but disclosed polyclonality. Most of the B-cell lymphomas showed immunophenotypes for B-cell lineages with their κ: λ or λ: κ ratio being over 3:1. In T-cell lymphomas, T-cell surface markers were predominantly expressed as well. In conclusion, our results suggest that immunophenotyping of lymph node aspirates is a valuable diagnostic adjunct for lymphoproliferative disorders, particularly in B-cell lymphomas because immunophenotyping can be easily and adequately performed by FCM.