A spectrum of monoclonal gammopathies due to clonal proliferation of a plasma cell line. They are collective know as plasma cell dyscrasia. One notable exception to the rule is non-secretory myeloma.
Monoclonal gammopathy of undetermined significance
This dyscrasia is common in older patients. The gammopathy is a result of a small secretory population of clonal plasmacytes. MGUS is characterised by minor marrow involvement with <10% of total nucleated cells, absence of CRAB criterion, and no identifiable bone or soft tissue plasmacytoma or amyloidosis.
Smouldering multiple myeloma
Solitary plasmacytoma
A clonal proliferation of plasma cells in bone or soft tissue. It typically presents with symptoms secondary to the growing mass. Its diagnosis requires a biopsy proven clonal plasmacyte population and absence of end organ involvement.
Multiple myeloma
Multiple myeloma is a malignant dyscrasia, it is the endpoint on the spectrum of plasma cell dyscrasias and has determined significance. Almost all multiple myeloma develops through transformations from monoclonal gammopathy of undetermined significance. Death is brought about by end-organ failure as a result of antibody deposition.
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