<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A type of cancer that begins in plasma cells (white blood cells that produce antibodies). A plasmacytoma may turn into multiple myeloma.</n0:def-definition><n0:def-source>NCI-GLOSS</n0:def-source></n0:ComplexDefinition>
<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A malignant (clonal) proliferation of plasma cells that are cytologically and immunophenotypically identical to those of plasma cell myeloma, but manifest a localized osseous or extraosseous growth pattern. (WHO, 2001)</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>