What are plasma cell neoplasms and related disorders?

• Plasmacytoma: solitary neoplasm of clonal plasma cells without evidence of plasma cell (multiple) myeloma or end-organ damage due to plasma cell neoplasia. • Plasma cell myeloma is a bone marrow-based, multifocal neoplastic proliferation of plasma cells. • Multiple myeloma is defined by the combination of : – plasma cell myeloma, – usually associated with a serum and/or urine monoclonal immunoglobulin, – and either evidence of organ damage related to the disease – or in the absence of organ damage, laboratory or imaging findings that suggest a high risk of developing end-organ damage within 2 years