Clinical Report: Non-IgM Lymphoplasmacytic Lymphoma Lacking CD19 Expression

Background

Lymphoplasmacytic lymphoma (LPL) is a rare B-cell lymphoma, often associated with IgM paraprotein secretion and classified as Waldenström’s macroglobulinemia (WM). Approximately 5% of LPL cases present as non-IgM type, which can complicate diagnosis due to atypical immunophenotypes, such as CD19 negativity. Understanding these variations is essential for accurate diagnosis and management.

Data Highlights

No numerical or trial data presented in the article.

Key Findings

• A 69-year-old man was diagnosed with CD19-negative non-IgM type LPL.
• Bone marrow biopsy showed approximately 40% cellularity with interstitial infiltration of CD20+ B lymphocytes.
• Molecular testing confirmed the MYD88 L265P mutation and absence of CXCR4 mutation.
• CD19-negative clonal plasma cells were identified, which is atypical for LPL.
• The case emphasizes the need for a multi-platform diagnostic approach in hematologic malignancies.

Clinical Implications

Clinicians should be aware of the possibility of CD19-negative clonal populations in LPL, which may lead to misdiagnosis if not properly evaluated.

Conclusion

This case illustrates the complexities of diagnosing non-IgM type LPL, particularly with atypical immunophenotypes such as CD19 negativity.

Related Resources & Content

1. Frontiers in Oncology, 2026 -- CD19-Negative Non-IgM Type Lymphoplasmacytic Lymphoma: A Case Report and Literature Review
2. Report of Consensus Panel 4 from the 12th International Workshop on Waldenstrom's Macroglobulinemia on the management of patients with non-IgM lymphoplasmacytic lymphoma, 2025
3. Blood Cancer Journal — Macrophages Expressing PDL1 Infiltrate Diffuse Large B-Cell Lymphoma and Enhance Tumor Growth in a MYC-Driven Experimental Model
4. Frontiers in Oncology — Primary diffuse large b-cell lymphoma of the lip: a case report and literature review
5. Blood Cancer Journal — CNS Relapses of Diffuse Large B Cell Lymphoma Show Absence of Oncogenic MYD88 and CD79B Mutations
6. Frontiers in Oncology — Coexistence of lymphoplasmacytic lymphoma and multiple myeloma: a case report and review of literature
7. Report of Consensus Panel 4 from the 12th International Workshop on Waldenstrom's Macroglobulinemia on the management of patients with non-IgM lymphoplasmacytic lymphoma
8. Frontiers | CD19-Negative Non-IgM Type Lymphoplasmacytic Lymphoma: A Case Report and Literature Review
9. Lymphoplasmacytic lymphoma with IgG or IgA paraprotein: a study of 29 cases including cases that can mimic plasma cell neoplasms - PubMed
10. Waldenström’s macroglobulinemia: The LYSA pragmatic guidelines - ScienceDirect
11. Multi-omics analysis reveals a unique epigenetic signature in MYD88 wild-type Waldenström macroglobulinemia | Haematologica