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.

多发性骨髓瘤后曾报道继发性血液系统恶性肿瘤，例如 B 细胞急性淋巴细胞白血病/淋巴瘤 (B-ALL)。酪氨酸激酶抑制剂改善了费城阳性 (Ph+) B-ALL 患者的临床结果。因此，识别 B-ALL 患者的 Ph 染色体对于预后和治疗都很重要。我们介绍了多发性骨髓瘤后继发性 Ph+ B-ALL 的病例，该病例通过基因融合分析突出了BCR::ABL1融合，以揭示隐蔽的 Ph 染色体，否则传统细胞遗传学和典型的间期荧光原位杂交可能会遗漏该染色体。