유세포분석기 세포 분류 후 FISH 기법을 이용한 만성골수백혈병과 필라델피아 양성 B-림프모구백혈병의 감별: 증례보고

Abstract

Distinguishing between chronic myeloid leukemia (CML) in B-lymphoblastic crisis and B-cell acute lymphoblastic leukemia (B-ALL) with BCR::ABL1 fusion is important in establishing treatment plans, since hematopoietic stem cell transplantation is usually advised in the former case but is more situational in the latter. However, the morphological and flow cytometric similarities between leukemic blast cells make the clear diagnostic distinction between these two diseases challenging. Nonetheless, the fact that the BCR::ABL1 gene fusion is present only in lymphoblasts in B-ALL, whereas it is also observed in non-blast cells (e.g., neutrophils) in CML in B-lymphoblastic crisis, can be leveraged to obtain a definitive diagnosis. However, although various methods to exploit this key feature difference have been proposed, a widely accepted standardized protocol has not yet been established. This case report introduces a new protocol that enhances the convenience and accuracy of making this disease distinction. We present the case of a patient whose initial diagnosis of B-ALL was re-evaluated after flow cytometry was used to sort bone marrow cell populations into blasts and neutrophils, and these cells were subsequently separately tested for the BCR::ABL1 fusion using FISH. This approach led to a final diagnosis of CML in B-lymphoblastic crisis.