Plasma cell leukemia accompanied by polyclonal gammopathy and congenital tumor in the atrioventricular node

A 32-year-old man with plasma cell leukemia and congenital tumor of the atrioventricular node is described. Although M protein could not be detected by immunoelectrophoresis, the examination of bone marrow atypical plasma cells with immunofluorescent and immunoperoxidase showed that most of these plasma cells produced IgG or IgA. Also some plasma cells possessed concomitantly both IgG and IgA. An electrocardiogram revealed complete atrioventricular block. The patient died of aspergillosis and bleeding in the lung. Postmortem examination revealed the infiltration of atypical plasma cells in the bone marrow, spleen, liver and lungs, and infiltration of mesothelial tumor cells in the atrioventricular node.