Secondary hematologic malignancies, such as B-cell acute lymphoblastic leukemia/lymphoma (B-ALL), have been reported following multiple myeloma. Tyrosine kinase inhibitors have improved clinical outcomes of patients with Philadelphia-positive (Ph+) B-ALL. Therefore, recognition of the Ph chromosome in B-ALL patients is important for both prognosis and therapies. We present a case of a secondary Ph+ B-ALL following multiple myeloma that highlights a BCR::ABL1 fusion by a gene fusion assay to reveal a cryptic Ph chromosome, which may otherwise be missed by conventional cytogenetics and typical interphase fluorescence in situ hybridization.
Keywords: B-cell acute lymphoblastic leukemia/lymphoma; Fluorescence in situ hybridization; Gene fusion assay; Karyotype; Multiple myeloma; Philadelphia-positive; Tyrosine kinase inhibitors.
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