ABSTRACT
Introduction The presence of clonal plasma cells (PCs) can be associated w ith a variety
of manifestations, ranging from the asymptomatic laboratory finding of mono clonal gammopathy of undetermined significance (M GUS) to the aggressive fatal course o f plasma cell leukemia (PCL). Bone marrow (BM ) plasmacytosis may also be seen as a reactive phenomenon w ith clin ical findings that are dominated by the underlying process. Lymphoplasmacytic lymphoma (LPL) w ill also be discussed in this chapter, because it has in common w ith the other PC disorders the production of monoclonal immunoglobulin as well as some morphologic features.
