Figure 4: Smears produced from lymph node fine-needle samples and examined at high power. High power assessment shows the differences in cell composition between reactive lymphoid hyperplasia (a) and the cytological features of the neoplastic cells in marginal zone lymphoma (b), follicular lymphoma (c), mantle cell lymphoma (d), chronic lymphocytic leukemia/small lymphocytic lymphoma (e), and lymphoplasmacytic lymphoma (f). Follicular dendritic cells (black arrowheads), tingible body macrophages (black arrow) and mitoses (white arrows) are present within a lymphohistiocytic aggregate seen in reactive lymphoid hyperplasia. Monocytoid B-cells (red arrow) and plasmacytoid cells (white arrowheads) are often found in marginal zone lymphoma. Follicular dendritic cells are a prominent feature of follicle center fragments present in samples of follicular lymphoma. These follicle center fragments do not show the other constituents seen in the lymphohistiocytic aggregates of a reactive lymph node. Mitoses are also a frequent finding in mantle cell lymphoma, but are not commonly seen in the other types of B-cell non-Hodgkin lymphoma illustrated here. Prolymphocytes (red arrowheads) are often found in areas of vague nodularity present in smears of chronic lymphocytic leukemia/small lymphocytic lymphoma and identified by a nucleolus which has a tinctorial quality similar to the cytoplasm of the cell. Plasmacytoid cells and mast cells (f: left lower image quadrant) are constituents seen in lymphoplasmacytic lymphoma. (d: Diff-Quik, all other: May-Grünwald-Giemsa; 63x).