Waldenström macroglobulinemia (WM) is a rare blood cancer in which abnormal B lymphocytes produce excessive amounts of an antibody called immunoglobulin M (IgM). The abnormal cells can accumulate in the bone marrow and interfere with normal blood-cell production. High levels of IgM can also make the blood thicker than normal, potentially causing circulation and neurological problems. Treatment depends on symptoms, IgM levels, disease activity, overall health, and specific genetic characteristics.
Waldenström macroglobulinemia is a type of lymphoplasmacytic lymphoma, a rare B-cell non-Hodgkin lymphoma.
The abnormal cells primarily accumulate in the bone marrow but may also involve lymph nodes and the spleen.
A genetic change involving the MYD88 gene is found in many cases and can help support diagnosis.
Some people have no symptoms when WM is first detected.
When symptoms occur, they may include:
Symptoms can also result from excessive IgM in the bloodstream.
High IgM levels can make blood more viscous, a complication known as hyperviscosity syndrome.
Possible symptoms include:
Severe hyperviscosity can become a medical emergency.
Diagnosis generally involves blood testing, bone marrow evaluation, and specialized laboratory studies.
Testing may include:
These tests help distinguish WM from other blood cancers that can also produce abnormal proteins.
Not everyone with WM needs immediate treatment.
People without symptoms or significant complications may be monitored through active surveillance.
Treatment is generally considered when the disease causes clinically significant problems, such as:
The decision to begin treatment is individualized.
Treatment may include several approaches depending on the clinical situation.
Possible therapies include:
Treatment strategies continue to evolve as new targeted therapies become available.
Targeted medications can interfere with signaling pathways that help abnormal B cells survive.
Bruton tyrosine kinase (BTK) inhibitors are an important treatment class for WM. Examples include:
These medications may be used alone or as part of combination treatment depending on the circumstances.
Monoclonal antibodies can target proteins on abnormal B cells.
Rituximab, which targets CD20, is commonly used in WM treatment and may be combined with other medications.
The treatment approach depends on disease characteristics and previous therapy.
When high IgM causes symptomatic hyperviscosity, plasmapheresis can rapidly remove IgM from the bloodstream.
It can provide rapid symptom relief but generally does not eliminate the underlying malignant cells, so additional disease-directed treatment is usually needed.
Regular follow-up helps evaluate disease activity and treatment response.
Monitoring may include:
Treatment may be modified based on response and side effects.
WM is generally considered a chronic condition that can often be managed for many years.
Long-term care may include:
The course of disease varies considerably between individuals.
Urgent medical care is important for symptoms such as:
These symptoms can occur with serious complications such as hyperviscosity or other medical emergencies.
Waldenström macroglobulinemia is a rare B-cell blood cancer characterized by abnormal lymphoplasmacytic cells and excessive IgM production. Some people can be monitored without immediate treatment, while symptomatic disease may require targeted therapy, immunotherapy, chemotherapy, or other approaches. Plasmapheresis can rapidly reduce IgM during symptomatic hyperviscosity. Regular monitoring and individualized treatment planning with a hematology team are essential for managing the disease and its complications.