{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T05:04:52Z","timestamp":1783919092352,"version":"3.55.0"},"reference-count":17,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T00:00:00Z","timestamp":1783900800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Oncol."],"abstract":"<jats:p>\n                    Lymphoplasmacytic lymphoma (LPL) that does not fulfill the diagnostic criteria for Waldenstr\u00f6m\u2019s macroglobulinemia (WM), termed non-IgM type LPL, represents a rare entity that poses significant diagnostic challenges. Here, we report a rare case of CD19-negative non-IgM type LPL. A 69-year-old man was incidentally found to have elevated M-protein and globulin levels during a routine health examination. Subsequent evaluation revealed elevated serum IgG, an IgG-\u03bb monoclonal protein, and markedly elevated urinary \u03bb free light chains. Bone marrow biopsy demonstrated normocellular marrow with approximately 40% cellularity. Immunohistochemistry revealed that CD20\n                    <jats:sup>+<\/jats:sup>\n                    B lymphocytes predominated over CD3\n                    <jats:sup>+<\/jats:sup>\n                    T lymphocytes, exhibiting an interstitial infiltration pattern. PAX5 staining highlighted B lymphocytes, comprising approximately 30% of total nucleated cells. CD138 staining revealed plasma cells in a scattered and clustered distribution, accounting for 3\u22125% of nucleated cells. Flow cytometry identified a monoclonal B lymphocyte population that was CD19-negative and CD20-positive, with restricted \u03bb light chain expression, coexisting with a monoclonal plasma cell population showing restricted cytoplasmic \u03bb light chain expression. Although the bone marrow biopsy lacked characteristic lymphoid aggregates, molecular testing confirmed the presence of the\n                    <jats:italic>MYD88<\/jats:italic>\n                    L265P mutation and the absence of the\n                    <jats:italic>CXCR4<\/jats:italic>\n                    mutation. The integration of morphological, immunophenotypic, and molecular findings with clinical features established the diagnosis of CD19-negative non-IgM type LPL. This case underscores the critical role of a comprehensive, multi-platform diagnostic approach and effective clinician-laboratory communication in accurately diagnosing hematologic malignancies with atypical immunophenotypes.\n                  <\/jats:p>","DOI":"10.3389\/fonc.2026.1809955","type":"journal-article","created":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T04:23:30Z","timestamp":1783916610000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["CD19-negative non-IgM type lymphoplasmacytic lymphoma: a case report and literature review"],"prefix":"10.3389","volume":"16","author":[{"given":"Feng","family":"Lu","sequence":"first","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fugang","family":"Li","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongying","family":"Zhan","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuanfeng","family":"Huang","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rong","family":"Huang","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xuchuan","family":"Jiang","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chengjie","family":"Ji","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gang","family":"Wang","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tao","family":"Chen","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xia","family":"Fu","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tao","family":"Wei","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Weijie","family":"Jiang","sequence":"additional","affiliation":[{"name":"The People\u2019s Hospital of Jianyang City","place":["Jianyang, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,7,13]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1182\/blood.2022015851","article-title":"The international consensus classification of mature lymphoid neoplasms: a report from the clinical advisory committee","volume":"140","author":"Campo","year":"2022","journal-title":"Blood"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1038\/s41375-022-01620-2","article-title":"The 5th edition of the world health organization classification of haematolymphoid tumours: lymphoid neoplasms","volume":"36","author":"Alaggio","year":"2022","journal-title":"Leukemia"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1002\/ajh.27666","article-title":"Waldenstr\u00f6m Macroglobulinemia: 2025 update on diagnosis, risk stratification, and management","volume":"100","author":"Gertz","year":"2025","journal-title":"Am J Hematol"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1038\/modpathol.2009.34","article-title":"Novel immunophenotypic features of marrow lymphoplasmacytic lymphoma and correlation with Waldenstr\u00f6m's macroglobulinemia","volume":"22","author":"Morice","year":"2009","journal-title":"Mod Pathol"},{"key":"B5","doi-asserted-by":"publisher","first-page":"47","DOI":"10.1016\/j.humpath.2022.10.005","article-title":"Lymphoplasmacytic lymphoma with IgG or IgA paraprotein: a study of 29 cases including cases that can mimic plasma cell neoplasms","volume":"130","author":"Qiu","year":"2022","journal-title":"Hum Pathol"},{"key":"B6","doi-asserted-by":"publisher","first-page":"43","DOI":"10.1053\/j.seminhematol.2024.01.004","article-title":"A tower of babel of acronyms? 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