RESUMEN
A 67-year-old woman presented with impaired general performance, suffering from fatigue, dyspnea on exertion, and paresthesia of the finger tips. The laboratory findings showed increased white blood cells at 11.37 x 10(3)cells/microl with 26.5% abnormal cells, low haemoglobin and, elevated creatinine, although serum lactate dehydrogenase and calcium levels were normal. Serum immunofixation was positive for monoclonal IgM-kappa paraprotein. Total serum protein and the IgM component were elevated. X-ray examination of the skeleton was normal. Bone marrow aspiration showed 59.5% infiltration of abnormal cells that were characterized by typical mature plasmacytoid morphology. Abnormal cells expressed surface CD20, surface CD138, and cytoplasmic IgM, but not surface CD56 nor surface IgM by flow cytometric immunophenotyping with CD38 gating. Immunohistochemistry showed surface CD38, surface CD20, and cytoplasmic IgM. The clinical findings led to the diagnosis of the IgM Plasma cell leukemia (PCL). The patient received multi-agent chemotherapy (VAD and EDAP with rituximab). The clinical symptoms disappeared, leading to the tumor load reduction. To the best of our knowledge, this is the first report of successful treatment of multi-agent chemotherapy with rituximab for IgM PCL.