IgM myeloma: a report of four cases.
ABSTRACT IgM myeloma is a rare disease, accounting for approximately 0.5% of multiple myelomas (MM). Here we report four cases of IgM multiple myeloma. Two were diagnosed in advanced clinical stages with multiple osteolytic lesions, leading to hypercalcemia in one patient. Bone marrow morphology showed a variable degree of infiltration with mainly mature plasma cells. An immunophenotypic analysis performed in one case showed expression of CD38 and monoclonal cytoplasmatic immunoglobulin. Interphase fluorescence in situ hybridization performed in one case did not reveal any aneuploidies or deletions of the retinoblastoma, P16, or P53 tumor suppressor genes. While one patient with a smoldering IgM myeloma did not need specific therapy, the others received cytotoxic treatment based on standard chemotherapy for MM. The outcomes were one stable disease, one sustained complete remission, and one progressive disease. All four patients were alive 1 year after diagnosis. One died due to progressive disease after 31 months. We conclude that IgM myeloma shares clinical and histological features with other MM rather than with Waldenström's macroglobulinemia, which is most commonly diagnosed in cases with IgM monoclonal gammopathy. Since MM and Waldenström's macroglobulinemia differ in prognosis and treatment strategies, the two disease entities should be distinguished based on clinical criteria, bone marrow morphology, and immunophenotypic analysis.
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ABSTRACT: IgM multiple myeloma (MM) is an extremely rare lymphoproliferative disease associated with an aggressive clinical course. However, the diagnosis of IgM MM may be complicated by Waldenstrom's macroglobulinemia (WM), particularly when clinical manifestations and morphological features are not typical. It is crucial to distinguish between IgM MM and WM as their prognoses and treatment strategies are different. We report a case of IgM MM presenting with bleeding tendency and an immunophenotype analysis using flow cytometry and immunohistochemistry. Bone marrow cells exhibited a typical phenotype for plasma cells, expressing monoclonal cytoplasmatic IgL-λ, CD38 and CD138 instead of pan-B cell antigens CD19, CD20 and CD22, which are characteristic of the typical immunophenotype of WM. Therefore, the diagnosis of IgM MM was confirmed in this case, highlighting the significance of detailed immuno-phenotypic evaluation when clinical and morphological features are atypical.Oncology letters 01/2011; 2(1):55-57. · 0.99 Impact Factor
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ABSTRACT: Peripheral neuropathy associated with monoclonal gammopathy is a rare but important cause of neuropathy that can herald serious underlying disease. IgM monoclonal gammopathy of undetermined significance (MGUS) is the most commonly found monoclonal gammopathy associated with neuropathy, with characteristic clinical, electrophysiologic, and pathologic features. The IgG and IgA monoclonal gammopathies are rarely associated with specific neuropathies. Standard immunomodulatory agents including steroids, intravenous immunoglobulin, and plasmapheresis have shown limited efficacy in IgM MGUS. Neuropathies associated with specific lymphoproliferative disorders may not respond to treatments aimed at that disorder. Case series had shown promising results with rituximab, a monoclonal antibody that targets the B cell surface antigen CD20 and results in a rapid and sustained depletion of B cells; however, two recent randomized controlled trials with rituximab failed to provide evidence of efficacy in primary outcome measures, despite reduction in antibody levels. Long-term studies looking at the association between specific immunologic markers and disease recurrence are needed to ultimately develop targeted therapies.Current Neurology and Neuroscience Reports 11/2011; 12(1):102-10. · 3.78 Impact Factor