Waldenström macroglobulinemia (WM) is synonymous with lymphoplasmacytic lymphoma as well as the presence of a monoclonal immunoglobulin (Ig) M gammopathy.
Most cases are associated with a mutation in MYD88, which offers a better prognosis than MYD88 wild-type cases.
CXCR4 mutations are associated with increased IgM levels and a higher risk of hyperviscosity.
Patients with WM are at risk for symptomatic hyperviscosity syndrome, which may present with visual disturbances, dizziness, cardiopulmonary symptoms, decreased consciousness, and a bleeding diathesis. Therapy for hyperviscosity consists of prompt initiation of plasma exchange followed by systemic therapy.
As with other low-grade lymphoid malignancies, asymptomatic patients and those without significant cytopenias or other end-organ manifestations can be observed with close follow-up.
Therapy should be initiated for symptomatic hyperviscosity, hemoglobin less than 10 g/dL, platelet count 100,000 K/uL or less, bulky adenopathy, symptomatic organomegaly, symptomatic cryoglobulinemia, or significant peripheral neuropathy
Waldenström macroglobulinemia (WM) is an uncommon, low-grade malignancy characterized by the presence of lymphoplasmacytic cells together with the presence of a monoclonal immunoglobulin (Ig) M paraproteinemia.1 The median age at diagnosis is between 63 and 68 years of age, men are more commonly affected than women, and the disease is more common among whites than those of other populations.2 Approximately, 90% of WM cases are associated with a mutation of the myeloid differentiation primary response 88 (MYD88) gene located on chromosome 3p22. WM cases having wild-type MYD88 are associated with worse outcomes and a higher propensity to transform into an aggressive lymphoma compared with cases having the MYD88 mutation.3–11 Of WM cases having the MYD88 mutation, approximately one third also have a mutation of chemokine receptor 4 (CXCR4); CXCR4 mutations are often associated with higher IgM levels and therefore increased risk of hyperviscosity.11,12
CLINICAL PRESENTATION AND DIAGNOSTIC WORK-UP
Many patients with WM are asymptomatic at the time of diagnosis. When symptoms develop, they are caused by tumor infiltration (cytopenias, hepatomegaly, splenomegaly), circulating IgM (hyperviscosity, cryoglobulinemia, cold agglutinin anemia), or tissue deposition of IgM (neuropathy, glomerular disease, amyloidosis). Patients with symptomatic hyperviscosity syndrome may present with visual disturbances, dizziness, cardiopulmonary symptoms, decreased consciousness, and a bleeding diathesis. Polyneuropathies are common. Some are associated with antigenic targets of the monoclonal serum IgM, including myelin-associated glycoprotein (MAG) and sulfatide. Others are caused by direct tumor infiltration, tissue deposition of IgM, the amount and properties of the circulating monoclonal IgM, binding of unidentified antigens, or associated amyloidosis.2 Patients may also present with cold or warm autoimmune hemolytic anemia, iron-deficiency anemia, or dilutional anemia.2
Initial evaluation (Table 15–1) of patients with suspected WM should include a complete blood count with differential, serum chemistries, liver function tests, viral hepatitis serologies, serum protein electrophoresis (SPEP) and immunofixation, quantitative immunoglobulin levels, and a β2-microglobulin. In patients suspected of having cryoglobulinemia, a cryocrit should be drawn and together ...