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Case Report: A case of non-secretory multiple myeloma presenting with eosinophilia: diagnostic challenges and a focused literature review

Year: 2026

Type: article

Abstract: We report a rare case of non-secretory multiple myeloma (NSMM) presenting with marked eosinophilia and considerable diagnostic difficulty. A 56-year-old man was admitted with recurrent low back pain of more than 10 years’ duration that had rapidly worsened over the preceding 10 days, accompanied by diffuse pain and weight loss. Laboratory evaluation showed persistent eosinophilia, thrombocytopenia, elevated lactate dehydrogenase, and increased inflammatory markers. Imaging revealed multifocal osteolytic lesions involving the skull, vertebrae, ribs, and pelvis. However, serum and urine immunofixation electrophoresis were negative, qualitative urine Bence-Jones protein testing was negative, and repeated serum free light chain testing showed a normal κ/λ ratio, making the diagnosis particularly challenging. Bone marrow aspirate showed marked eosinophilia, and flow cytometry identified clonal plasma cells accounting for 6.1% of nucleated cells. Bone marrow biopsy with immunohistochemistry confirmed a plasma-cell neoplasm, while myeloma fluorescence in situ hybridization (FISH) revealed 1q21 gain/amplification together with chromosome 13-related abnormalities, including RB1 deletion and D13S319 abnormality. After exclusion of secondary and primary/clonal eosinophilic disorders, the patient was diagnosed with NSMM with eosinophilia. This case highlights the diagnostic challenge posed by the coexistence of marked eosinophilia and NSMM, which obscured the underlying plasma-cell malignancy despite repeatedly negative monoclonal protein studies. We also reviewed the limited literature on MM-associated eosinophilia to underscore the importance of integrating bone marrow findings, imaging, and cytogenetic evaluation in atypical cases.

Source: Frontiers in Oncology

DOI: 10.3389/fonc.2026.1833556

Authors: Jirui Zhong, Xikun Liu, Jiduo Liu, Shanshan Xiao, Xuekui Gu, Zenghui Liu

Institutions: Guangzhou University of Chinese Medicine, First Affiliated Hospital of Guangzhou University of Chinese Medicine

Language: English

Topic: Multiple Myeloma Research and Treatments

Subfield: Hematology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $3,801