Extramedullary Presentation of Biclonal IgGk and IgAk Multiple Myeloma

Multiple myeloma is characterized by plasma cell infiltration of the bone marrow and the presence of a monoclonal protein in the plasma or the urine in 90% of cases. Major manifestations of the disease are bone pain, anemia, renal insufficiency and recurrent infections. Less frequent presentations are hepatic and splenic enlargement (5% of cases), lymphadenopathy (4%) and biclonal gammopathy (1%). In this report we describe a biclonal multiple myeloma presenting with cervical lymphadenopathy and sternal mass. The immunohistochemical study of the lymph node and the flow cytometric analysis of the bone marrow showed IgGk and IgAk biclonality. In this report the features of lymph node involvement and biclonality constitute a rare presentation of multiple myeloma.