Secondary light chain amyloidosis with Waldenström's macroglobulinemia and intermodal marginal zone lymphoma: A case report

Background: The co-existence of Waldenström's macroglobulinemia (WM) with internodal marginal zone lymphoma (INMZL) is rare and often associated with poor prognosis.

Case summary: We present a Chinese female patient who developed secondary light chain amyloidosis due to WM and INMZL and provides opinions on its systemic treatment. A 65-year-old woman was diagnosed with WM 6 years ago and received Bruton tyrosine kinase inhibitor monotherapy for two years. Her INMZL was confirmed due to left cervical lymphadenopathy. The patient presented with oedema in both lower limbs one year ago, and was diagnosed with secondary light chain amyloidosis. Treatment with the BC regimen (rituximab 375 mg/m² monthly for 6-8 courses, and bendamustine 90 mg/m² per day × 2, monthly for six courses) was initiated, but not tolerated due to toxic side effects. Bortezomib-based therapy was given for two months, including bortezomib, dexamethasone, and zanubrutinb. Oedema in both lower limbs was relieved and treatment efficacy was evaluated as partial remission.

Conclusion: A detailed clinical evaluation and active identification of the aetiology are recommended to avoid missed diagnosis and misdiagnosis.