FLOW CYTOMETRIC AND IMMUNOHISTOCHEMICAL ANALYSIS OF SMALL LYMPHOCYTICLYMPHOMA, MANTLE CELL LYMPHOMA, AND PLASMACYTOID SMALL LYMPHOCYTIC LYMPHOMA

Small lymphocytic lymphoma (SLL), mantle cell lymphoma (MCL), and SLL plasmacytoid (SLLP) are malignant neoplasms of small B cells that may have overlapping cytologic features. Entities such ns SLL with irregul ar nuclear contours may pose additional diagnostic difficulties. We in vestigated the utility of flow cytometric analysis and immunohistochem istry studies in distinguishing these disorders from each other We rev iewed 29 lymphomas and classified them as SLL (13 cases), MCL (8 cases ), and SLLP (8 cases) based on histology and expression of cytoplasmic immunoglobulin light chain. Paraffin section immunohistochemistry was performed for CD5, CD20, CD23, CD43, CD45RA, CD45RO, and kappa and la mbda light chains. Flow cytometric analysis was carried out by 2-color direct immunofluorescence for CD5, CD11c, CD19, CD20, CD22, CD23, FMC 7, and kappa and lambda light chains. By immunohistochemistry we found that the expression of CD23 in SLL discriminates between SLL and MCL and that the expression of CD23 and CD43 in SLL discriminates between SLL and SLLP. By flow cytometric analysis, we found that CD11c(+) and dim fluorescence intensity of sIg and dim fluorescence intensity of FM C7 in SLL distinguish SLL from MCL, and the expression of CD5(+), CD23 (+) and dim fluorescence intensity of FMC7 in SLL distinguishes SLL fr om SLLP. We found no immunophenotypic difference between SLL and SLL w ith irregular nuclear contours.