Lymphoplasmacytic non-Hodgkin lymphoma/Waldenström's macroglobulinemia with CD5+, CD23+, and CD10-

300 Letters to the Editor Table 1. Diagnostic criteria for Wladenström's macroglobulinemia and IgM monoclonal gammopathy of undetermined significance. Wladenström's macroglobulinemia a) IgM monoclonal gammopathy of any entity b) Lymphomatous bone marrow infiltration by lymphocytes with clonal plasmacytoid differentiation c) Intertrabecular bone marrow infiltration d) Immunophenotype lymphoplasmacytic bone marrowIgM monoclonal gammopathy of undetermined significance a) Serum IgM monoclonal component ＜3 g/dL b) No morphological evidence of bone marrow lymphoplasmacytic infiltration (even in the presence of evident immunophenotypic or molecular clonality) c) Neither symptoms or signs due to the tumor infiltration d) Neither symptoms or signs due to the serum IgM monoclonal component No potential conflicts of interest relevant to this article were reported. Acute leukemia during pregnancy: a report on 37 patients and a review of the literature. Lymphoplasmacytic non-Hodgkin lymphoma/WaldenströmÊs macro-globulinemia with CD5+, CD23+, and CD10-TO THE EDITOR: In lymphoplasmacytic lymphoma/Walden-ström's macroglobulinemia (LPL/WM), the immunopheno-type of the neoplastic population generally does not show positivity for CD5, CD23, or CD10 monoclonal antibodies, with only 5–20% showing positivity. However, this im-munophenotypic particularity does not exclude a diagnosis of Waldenström's macroglobulinemia; moreover, CD5 and/or CD23 monoclonal antibody positivity can characterize a subset of patients with high IgM values; these patients are at risk for hyperviscosity-related complications. WM was first described by Jan Waldenström in 1944 [1] and is classified as an indolent B-cell lymphoplasmacytic lymphoma (LPL) or LPL/WM [2]. It is a lymphoproliferative neoplasm characterized by the presence of a serum IgM monoclonal component associated with bone marrow lym-phocytic infiltration. According to the Workshop on WM held in Athens in 2002 [2], the diagnosis (Table 1) is principally based on the following two essential findings: 1) the quantitative presence of any serum IgM monoclonal component and 2) bone marrow infiltration by lymphoid cells with a lymphoplasmacytic aspect. In WM patients, the serum IgM monoclonal component concentration varies widely. However, while finding a mon-oclonal IgM component is a prerequisite for the LPL/WM diagnosis, it is not a specific feature of WM. In fact, an IgM monoclonal component can be found in other lympho-proliferative disorders, such as chronic lymphocytic leuke-mia/small lymphocytic lymphoma (CLL/SLL), splenic marginal zone lymphoma (SMZL), diffuse large cell lymphoma (DLCL), mantle cell lymphoma (MCL), myeloma and IgM monoclonal gammopathy of undetermined significance (IgM-MGUS)(Table 1). The lymphomatous nature of bone marrow infiltration must be confirmed using flow cytometry and immunohisto-chemistry to define the immunophenotype. Bone marrow infiltration, usually intertrabecular, is represented by …