Lecture 4. Clonal Plasma Cell Precursors.

Monoclonal gammopathy of undetermined significance (MGUS) is the term used for a minimal clonal expansion of plasma cells that is most typically detected by the presence of a small serum monoclonal protein. For most-but not all-patients, the presence of a small monoclonal protein will have no clinical significance at the time of recognition or even over time. It is imperative, therefore, that a careful-but sensible-evaluation be performed both at the time of recognition and subsequently because these monoclonal may represent significant pathology including diseases such as multiple myeloma, low grade lymphoma or any of the diseases captured under the moniker of monoclonal gammopathy of clinical significance (MGCS), which includes-but is not limited to-immunoglobulin light chain amyloidosis and POEMS syndrome. Herein is a discussion of the diagnosis and follow-up MGUS and MGCS.