Introduction
This topic covers multiple myeloma (plasma cell myeloma, myeloma disease), a disseminated malignant proliferation of clonal plasma cells in the bone marrow, and its localized counterpart, the solitary plasmacytoma of bone or of soft tissue. You should be able to define them, explain how the tumour causes bone destruction, abnormal proteins and organ damage, describe the morphology and name the complications and the outcome.
Definition and background
- Multiple myeloma is a monoclonal neoplasm of terminally differentiated B cells (plasma cells) that grows in the bone marrow at many sites and usually secretes a single immunoglobulin or part of one (M-protein, paraprotein).
- It is a disease of older adults (peak in the 6th to 7th decade), slightly more common in men, and more common in people of African descent.
- It belongs to the group of plasma cell dyscrasias (monoclonal gammopathies), which also includes MGUS, smouldering myeloma, Waldenström macroglobulinaemia, heavy chain disease and AL amyloidosis.