To report a rare case of concurrent lymphoplasmacytic lymphoma (LPL) and multiple myeloma (MM) and discuss diagnostic challenges.
Approach:
Case Presentation: A 68-year-old man presented with fatigue and bone pain, with laboratory findings indicating severe anemia, thrombocytopenia, and hyperglobulinemia. Imaging revealed osteolytic lesions, and bone marrow analysis identified distinct B-cell populations.
Molecular Testing: Next-generation sequencing confirmed MYD88 and CXCR4 mutations, supporting the diagnosis of LPL and active MM.
Key Findings:
The patient exhibited both LPL and MM, with dual monoclonal proteins identified.
Bone marrow flow cytometry revealed two distinct B-cell populations consistent with LPL and MM.
The presence of osteolytic lesions and severe anemia met the CRAB criteria for active MM.
Interpretation:
This case highlights the need for careful diagnostic evaluation to differentiate between plasmacytic differentiation and true biclonal disease.
Limitations:
Definitive proof of biclonality requires sorted-cell molecular studies, which were not performed.
The clonal plasma cell percentage was below the traditional 10% threshold for MM diagnosis.
Conclusion:
The case emphasizes the importance of integrating clinical, immunophenotypic, and molecular data in diagnosing concurrent LPL and MM.
