tailieunhanh - Ebook Handbook of hematologic malignancies: Part 2

Part 2 book “Handbook of hematologic malignancies” has contents: Multiple myeloma, hodgkin lymphoma, immunoglobulin light chain amyloidosis, burkitt lymphoma, double hit lymphoma, mantle cell lymphoma, primary central nervous system lymphoma, follicular lymphoma, marginal zone lymphoma, and other contents. | Plasma Cell Disorders 25 Monoclonal Gammopathy of Unknown Significance, Smoldering Myeloma, and Plasmacytomas Srinath Sundararajan, Abhijeet Kumar, Amit ­Agarwal, and Neha Korde INTRODUCTION Plasma cell (PC) dyscrasias are disorders characterized by clonal proliferation of PCs with or without elevated levels of monoclonal protein (M protein) and immunoglobulin fragments. It encompasses a number of disorders including monoclonal gammopathy of unknown significance (MGUS), smoldering myeloma (SMM), solitary plasmacytoma (SP), multiple myeloma (MM), PC leukemia, Waldenstrom’s macroglobulinemia (WM), and amyloidosis (AL). In this chapter, we focus on MGUS, SMM, and plasmacytoma (see Chapters 26–28). MONOCLONAL GAMMOPATHY OF UNKNOWN SIGNIFICANCE MGUS is an asymptomatic clonal PC disorder and is a precursor for MM. The incidence and prevalence of MGUS increases with age, with a prevalence in the United States estimated to be slightly greater than 3% in Whites who are 50 or older. In a population-based study from Olmstead County, Minnesota, the annual incidence of MGUS was noted to be 120 per 100,000 and 60 per 100,000 in men and women greater than 50 years, respectively (Mayo Clin Proc. 2010;85(10):933-942). In men and women greater than 90 years, the incidence of MGUS increased to 530 per 100,000 and 370 per 100,000, respectively. DIAGNOSIS The 2014 International Myeloma Working Group (IMWG) definition for MGUS is summarized in Table By definition, patients with MGUS are asymptomatic. Commonly, patients are diagnosed incidentally while being worked up for other disorders. Considering the lack of proven benefit, health care burden, and psychological implications, universal screening for MGUS is not advocated. The workup for MGUS needs to incorporate the tests to rule out more serious conditions, such as SMM or MM (Figure ). Bone marrow (BM) biopsy can be considered in patients who are less than 65 years and/or have high-risk MGUS (Figure ). 147 148