Lymphoplasmacytic lymphoma/Waldenström Macroglobulinemia Research Articles

Immunophenotypic Profile of Lymphoplasmacytic Lymphoma/Waldenström Macroglobulinemia

We retrospectively reviewed the immunophenotypic profile of 75 cases of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM) analyzed by flow cytometry. All patients had monoclonal IgM (median, 2,100 mg/dL [21 g/L]) in serum and were considered clinically to have WM. The neoplastic cells, in all cases, expressed monoclonal immunoglobulin light chain (k, 55; l, 20) and CD19, and every case assessed was positive for CD20 (n=68) and CD52 (n=60). The results for other antigens assessed in decreasing frequency of positivity were as follows: surface IgM (26/28 [93%]), CD79b (11/13 [85%]), CD11c (13/16 [81%]), CD25 (5/7 [71%]), CD23 (17/28 [61%]), CD38 (24/50 [48%]), FMC7 (11/29 [38%]), CD22 (4/12 [33%]), CD5 (3/65 [5%]), and CD10 (1/38 [3%]). These results show that the immunophenotype of LPL/WM is variable and overlaps with other B-cell lymphoproliferative disorders. CD23, usually of dim intensity, and CD11c are expressed commonly in LPL/WM. Rare CD5+ and CD10+ cases of LPL/WM also exist.

Immunophenotypic Profile of Lymphoplasmacytic Lymphoma/Waldenström Macroglobulinemia

We retrospectively reviewed the immunophenotypic profile of 75 cases of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM) analyzed by flow cytometry. All patients had monoclonal IgM (median, 2,100 mg/dL [21 g/L]) in serum and were considered clinically to have WM. The neoplastic cells, in all cases, expressed monoclonal immunoglobulin light chain (κ, 55;λ, 20) and CD19, and every case assessed was positive for CD20 (n = 68) and CD52 (n = 60). The results for other antigens assessed in decreasing frequency of positivity were as follows: surface IgM (26/28 [93%]), CD79b (11/13 [85%]), CD11c (13/16 [81%]), CD25 (5/7 [71%]), CD23 (17/28 [61%]), CD38 (24/50 [48%]), FMC7 (11/29 [38%]), CD22 (4/12 [33%]), CD5 (3/65 [5%]), and CD10 (1/38 [3%]). These results show that the immunophenotype of LPL/WM is variable and overlaps with other B-cell lymphoproliferative disorders. CD23, usually of dim intensity, and CD11c are expressed commonly in LPL/WM. Rare CD5+ and CD10+ cases of LPL/WM also exist.

Lymphoid Neoplasms Associated With IgM Paraprotein

We identified 382 consecutive patients with lymphoid neoplasms associated with serum monoclonal IgM paraprotein and classified each neoplasm according to World Health Organization criteria. Lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM) was most common, 225 cases (median serum IgM level, 2.2 g/dL; range, 0.2-10.9 g/dL). For 157 cases, classification and median (and range in g/dL) IgM levels were as follows: chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL; n = 77), 0.9 (0.1-2.1); marginal zone lymphoma (n = 27), 0.5 (0.1-2.4); follicular lymphoma (n = 18), 0.4 (0.1-1.6); mantle cell lymphoma (n = 11), 0.4 (0.2-1.3); diffuse large B-cell lymphoma (DLBCL; n = 7), 0.5 (0.2-1.0); DLBCL associated with low-grade lymphoma (n = 5), 0.9 (0.4-3.0); angioimmunoblastic T-cell lymphoma (n = 4), 0.8 (0.8); and CD5+CD23- low-grade B-cell lymphoma, unclassified (n = 8), 0.5 (0.3-2.9). The results show IgM paraproteinemia was associated most commonly with LPL/WM (58.9%), followed by CLL/SLL (20.2%). Although serum IgM levels greater than 3 g/dL were restricted to patients with LPL/WM, most patients with LPL/WM had paraprotein levels less than 3 g/dL. Thus, serum IgM paraprotein level is not a reliable discriminator in differential diagnosis.

Diffuse large B-cell lymphoma occurring in patients with lymphoplasmacytic lymphoma/Waldenström macroglobulinemia. Clinicopathologic features of 12 cases.

Of 92 patients with lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM) treated at our institution, diffuse large B-cell lymphoma (DLBCL) also developed in 12 (13%). In 10 patients, DLBCL developed 12 to 128 months (median, 44 months) after the diagnosis of LPL/WM. Two patients had LPL/WM and DLBCL simultaneously. Clinicopathologic features at diagnosis of LPL/WM did not predict the risk of DLBCL. Onset of DLBCL was characterized by worsening constitutional symptoms, profound cytopenias, extramedullary disease, and organomegaly. Immunoglobulin light chain expression was identical in both LPL/WM and DLBCL. In situ hybridization for Epstein-Barr virus (EBV) in 8 cases of DLBCL was negative. Of 11 patients with clinical follow-up information available, 8 (73%) died within 10 months of diagnosis of DLBCL. DLBCL, most likely as a result of histologic transformation, occurs in a subset of patients with LPL/WM and is associated with aggressive clinical course and poor outcome. EBV is unlikely to be involved in transformation.