Synopsis
Confirm marrow lymphoplasmacytic lymphoma with an IgM paraprotein, recognise IgM-mediated emergencies and choose symptom-led therapy that avoids hyperviscosity, rituximab-flare and bleeding harm.
- WM requires an IgM monoclonal gammopathy plus marrow infiltration by lymphoplasmacytic lymphoma; serum IgM concentration alone does not establish the diagnosis.
- First-line confirmation is marrow aspirate and trephine with morphology, flow and MYD88 L265P testing; assess CXCR4 when it changes BTK-inhibitor expectations.
- Do not treat an asymptomatic IgM number: indications include symptomatic anaemia or cytopenia, hyperviscosity, bulky disease, B symptoms and clinically important IgM-mediated organ injury.
Key red flags
Retinal haemorrhage or venous engorgement, mucosal bleeding, confusion, ataxia, seizure or heart failure is symptomatic hyperviscosity and requires urgent plasma exchange.
Visual blur, retinal haemorrhage, mucosal bleeding, headache, vertigo, confusion or dyspnoea requires urgent exchange assessment.
Investigation priorities
Demonstrate lymphoplasmacytic lymphoma and distinguish plasma-cell and marginal-zone alternatives.
Management branches
SPEP or immunofixation detects monoclonal IgM.
- Assess hyperviscosity, neuropathy, haemolysis, cryoglobulin, renal, nodes, spleen, cytopenia and constitutional symptoms.
- Perform marrow morphology, flow and MYD88 with CT and selected t(11;14) or plasma-cell studies.
Key medicines
Therapeutic plasma exchangeExchange approximately 1–1.5 calculated plasma volumes urgently with albumin-based replacement under the apheresis protocol, repeating according to clinical response, fundal findings, IgM and viscosity rebound.
Bendamustine with rituximabGive bendamustine 90 mg/m² IV on days 1 and 2 with rituximab 375 mg/m² IV day 1 every 28 days for up to six cycles, modifying through the WM protocol and sequencing rituximab when flare risk is high.