Benign lymph node with double-positive T cells detected by FC on preoperative FNA. High-power magnification of the FNA specimen showing mostly small lymphocytes, plasmacytoid cells, and a number of larger, atypical cells. Diff-Quik, high power (a). FC showing a population of CD4- and CD8-coexpressing T cells (double-positive T cells), as seen in the upper right quadrant of the scatterplot (b). Low-power view of the excisional biopsy demonstrating the retained lymph node architecture with expanded follicles. H&E stain, low power (c). Higher-power view of a reactive lymphoid follicle showing an intact mantle zone and a germinal center with small lymphocytes and occasional tingible body macrophages. H&E stain, medium power (d).