Prognostic factors and indications for treatment of Waldenström's Macroglobulinemia

Waldenström's Macroglobulinemia (WM) is characterized by the presence of an IgM monoclonal protein regardless of its size, 10% or more bone marrow infiltration by small lymphocytes with a plasmacytoid or plasma cell differentiation. These cells usually have the following markers: IgM+, CD5^-, CD10^-, CD19⁺, CD20⁺ and CD23^-. Chronic lymphocytic leukemia as well as other lymphoproliferative disorders such as mantle cell, marginal zone and mucosa-associated lymphoid tissue (MALT) lymphoma must be excluded. Weakness or fatigue from anemia, fever, night sweats, or weight loss represent the most common symptoms. Hepatosplenomegaly may be a major feature. Anemia, thrombocytopenia, hyperviscosity or peripheral neuropathy may be prominent features. Systemic amyloidosis, renal insufficiency and cryoglobulinemia may also be seen. WM must be differentiated from smoldering Waldenström's Macroglobulinemia (SWM) which is an intermediate disease state characterized by an IgM protein ≥3 g/dL and/or a bone marrow containing ≥10% bone marrow lymphoplasmacytic infiltration but no end-organ damage such as symptomatic anemia, constitutional symptoms, hyperviscosity, symptomatic hepatosplenomegaly or lymphadenopathy.