Overview
Definition
A lymphoplasmacytic lymphoma characterized by bone marrow infiltration and the production of a monoclonal IgM immunoglobulin, leading to hyperviscosity.
Epidemiology
Rare, typically affects older Caucasian men.
Etiology & Risk Factors
- Acquired somatic mutation in the MYD88 gene (detected in >90% of cases)
Clinical Symptoms
- Hyperviscosity syndrome: Headaches, blurry vision, retinal hemorrhages ('sausage-link' veins), epistaxis
- Peripheral neuropathy
- Lymphadenopathy and splenomegaly
- Constitutional symptoms (fatigue, night sweats)
Clinical Approach
Diagnosis
- Monoclonal IgM spike on SPEP
- Bone marrow biopsy showing lymphoplasmacytic infiltration
- Positive MYD88 L265P mutation
Management
- Plasmapheresis (immediate therapy to remove IgM and decrease viscosity in symptomatic patients)
- Systemic therapy: Rituximab, BTK inhibitors (Ibrutinib), or chemo-immunotherapy (Bendamustine + Rituximab)
- Avoid Rituximab initially if IgM is very high (can cause a transient IgM flare)
Complications
- Stroke / Neurological deficits from hyperviscosity
- Congestive heart failure (high viscosity strains heart)
- Cryoglobulinemia