Therapy-related b-lymphoblastic leukemia following treatment for multiple myeloma with unusual surface light chain expression: a case report

Background

Therapy-related B-lymphoblastic leukemia (B-ALL) following treatment for multiple myeloma is a rare occurrence. Despite its rarity and the lack of recognition by the World Health Organization as a distinct disease entity, previous publications indicate its possible emergence following myeloma treatment.

Case presentation

The patient is a 65-year-old gentleman with a history of IgG kappa multiple myeloma, status post multiple lines of therapy. The patient presented with a fever, and a complete blood count showed cytopenia. Bone marrow morphologic evaluation revealed numerous blasts. Immunophenotypic analysis demonstrated that these blasts were B lymphoblasts, despite MYC and unusual surface kappa light chain expression. A diagnosis of B-ALL with surface kappa light chain expression post-myeloma treatment was made. Ancillary studies indicated that the B-ALL and the previous myeloma were clonally unrelated. Next-generation gene sequencing revealed pathogenic mutations in KDM6A and KRAS.

Conclusions

In summary, we present an interesting case of B-lymphoblastic leukemia with unusual surface light chain expression in a patient who has previously undergone myeloma treatment. This case represents therapy-related B-ALL. Although it has not been categorized as a WHO-recognized disease entity, our case provides additional evidence supporting that myeloma treatment, particularly lenalidomide therapy, is associated with secondary B-ALL. Furthermore, the ClonoSEQ test result in the current case indicates that therapy-related B-ALL is clonally unrelated to the preceding MM. The identification of new predominant clones in follow-up bone marrow samples of myeloma patients should alert clinicians to the possible emergence of a secondary B-cell neoplasm.

Full text

https://www.xiahepublishing.com/2771-165X/JCTP-2024-00046

The study was recently published in the Journal of Clinical and Translational Pathology.

Journal of Clinical and Translational Pathology (JCTP) is the official scientific journal of the Chinese American Pathologists Association (CAPA). It publishes high quality peer-reviewed original research, reviews, perspectives, commentaries, and letters that are pertinent to clinical and translational pathology, including but not limited to anatomic pathology and clinical pathology. Basic scientific research on pathogenesis of diseases as well as application of pathology-related diagnostic techniques or methodologies also fit the scope of the JCTP.

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