Diagnosis and Risk Stratification in Waldenström Macroglobulinemia

Waldenström macroglobulinemia (WM) is a B-cell lymphoma characterized by the presence of bone marrow lymphoplasmacytic infiltration and circulating monoclonal immunoglobulin M protein. The clinical presentation of WM is variable, ranging from gradually progressive cytopenias, organomegaly, fatigue, B symptoms, and peripheral neuropathy to the more emergent presentation with symptomatic hyperviscosity, cryoglobulinemia, hemolytic anemia–associated symptoms, acquired von Willebrand disease or acquired hemophilia–associated bleeding. Approximately 1 in 5 patients with WM are asymptomatic at diagnosis and classified as having smoldering WM, not requiring WM-directed therapy. Although WM typically has an indolent, relapsing-remitting course, the outcomes are heterogeneous. The prognosis of patients with WM is known to be impacted by certain clinical and laboratory features at initial presentation, with advanced age, elevated serum lactate dehydrogenase, and low serum albumin unfavorably affecting the outcome. Although complications such as histologic transformation or light and/or heavy chain (AL/ALH) amyloidosis are infrequent, their occurrence adversely influences the disease course. The International Prognostic Staging System for WM (IPSS-WM) is a validated model, often used in clinical practice, but needs to be reexamined in the current era. The discovery of the recurrent MYD88 L265P gain-of-function point mutation and the subclonal CXCR4 mutations has helped improve our understanding of the WM biology, and the prognostic impact of these mutations is under evaluation, with somewhat inconsistent findings thus far across studies. This review discusses the clinical presentation, diagnostic criteria, and prognostic markers of WM.