What is it? IgM monoclonal gammopathy and is categorized as a lymphoplasmacytic lymphoma (not quite like multiple myeloma that has clear plasmytic differentiation!)
- Hyperviscosity syndrome
- End-organ dysfunction from tissue deposition (hepatosplenomegaly)
- IgM monoclonal gammopathy
- >= 10% small lymphocytes with plasmacytoid differentiation
- Immunophenotype (cell surface markers like CD138+ and others)
- Can be hard to distinguish with other malignancies
- Waldenstrom vs CLL: CD5 negative if Waldenstrom
- Waldenstrom vs MM: CD56 negative if Waldenstrom
Treatment: the threshold to begin treatment is driven by symptoms and the exact regimen is patient specific based on tolerability considerations (drug side effects) and symptom profile: Bleeding concerns? How sick? Neuropathy?
- If hyperviscosity syndrome, must start plasmapheresis!!
- Rituximab can cause an IgM flare in 40-60% of patients and paradoxically worsen hyperviscosity initially!
- Serum viscosity test >4-6 (normal range 1.4-1.8) is when you can expect hyperviscosity symptoms