Waldenstrom macroglobulinemia
Waldenstrom macroglobulinemia is an indolent B-cell lymphoma of clonal lymphoplasmacytic cells that secrete monoclonal IgM, causing anemia, lymphadenopathy, and hyperviscosity syndrome without the lytic bone disease of myeloma. Diagnosis rests on serum IgM electrophoresis plus a bone marrow lymphoplasmacytic infiltrate, and symptomatic hyperviscosity is a hematologic emergency treated with emergent plasmapheresis alongside rituximab-based or BTK-inhibitor therapy.
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What this article covers
- Overview
Definition: Waldenstrom macroglobulinemia (WM) is an indolent B-cell lymphoma with clonal lymphoplasmacytic cells in the bone marrow or lymph nodes that secrete clonal IgM into the blood, and it is…
- Epidemiology
Rare compared with myeloma: WM is an uncommon plasma cell/lymphoplasmacytic dyscrasia, distinctly less common than multiple myeloma and monoclonal gammopathy of undetermined significance (MGUS).
- Risk factors
Preexisting IgM MGUS: the principal identifiable precursor state, progressing to WM at approximately 1.5% per year.
- Pathophysiology
Clonal lymphoplasmacytic proliferation: malignant lymphoplasmacytic cells expand in the bone marrow and lymph nodes and secrete clonal monoclonal IgM.
- Clinical features
Constitutional B symptoms: fatigue, fevers, drenching night sweats, and weight loss, often the presenting complaint.
- Differential diagnosis
Multiple myeloma: monoclonal IgG or IgA (not IgM) with lytic bone lesions, hypercalcemia, and renal failure from light-chain nephrotoxicity, distinguished by the CRAB features and the type of paraprotein (multiple myeloma).
- Diagnosis
Diagnosis rests on the marrow/M-protein/symptom triad that separates WM from MGUS: WM is confirmed by clonal lymphoplasmacytic cells comprising more than 10% of the bone marrow, a serum IgM…
- Management
Asymptomatic or smoldering WM: observe without therapy; treatment is reserved for patients with symptoms from the disease.
- Complications
Hyperviscosity syndrome: the defining emergency, with central nervous system dysfunction, visual and hearing loss, and mucosal bleeding if untreated.
- Prognosis
Indolent course: many patients have smoldering, asymptomatic disease that can be observed for years without therapy.
- Prevention
No primary prevention exists for WM itself; management instead centers on early recognition and monitoring of its precursor state.
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