Words to know: Waldenström macroglobulinemia
- Waldenström macroglobulinemia (WM)
- A rare, slow-growing blood cancer of B cells that make too much of the antibody protein IgM.
- Lymphoplasmacytic lymphoma
- The type of lymphoma that WM belongs to, made of cells that look like a mix of lymphocytes and plasma cells.
- B cell
- A white blood cell that makes antibodies to fight infection.
- IgM
- A large antibody protein. In WM, cancer cells make too much of it.
- M-spike
- The amount of abnormal protein seen on a blood test. It is used to track WM over time.
- Bone marrow
- The soft tissue inside bones where blood cells are made.
- Hyperviscosity
- Blood that is too thick, which can cause bleeding, vision changes, headaches, and confusion.
- Plasmapheresis
- A procedure where a machine removes plasma, the liquid part of the blood, to lower IgM quickly. Also called plasma exchange.
- Anemia
- Too few red blood cells, which can cause tiredness and shortness of breath.
- IgM MGUS
- An early, harmless-looking condition with a small amount of IgM protein and no symptoms.
- Smoldering WM
- WM that is present in the bone marrow but is not causing problems yet.
- Watch and wait
- Close follow-up with regular visits and tests instead of starting treatment right away.
- MYD88
- A gene that is changed in most cases of WM. Testing for it helps confirm the diagnosis.
- CXCR4
- A gene that is changed in some people with WM. It can affect how well BTK inhibitors work.
- BTK inhibitor
- A pill, such as zanubrutinib or ibrutinib, that blocks a signal WM cells need to grow.
- Rituximab
- An antibody medicine given by IV that attaches to B cells and helps destroy them.
- Bendamustine
- A chemotherapy drug often given with rituximab to treat WM.
- IgM flare
- A short-term rise in IgM that can happen after starting rituximab.
- Neuropathy
- Nerve damage that causes numbness, tingling, or pain, usually in the feet and hands.
- Anti-MAG antibody
- An IgM protein that attacks the coating of nerves and can cause neuropathy.
- Cryoglobulinemia
- When proteins in the blood clump in the cold, which can cause painful fingers and toes or skin sores.
- Atrial fibrillation
- An irregular, often fast heartbeat. It is a possible side effect of some BTK inhibitors.
- Bing-Neel syndrome
- A rare problem where WM cells reach the brain or spinal cord.
- Relapse
- When WM comes back or grows again after treatment.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.