急性微分化型髓细胞白血病转换为急性混合表型白血病一例诊断分析

Laboratory diagnosis of acute myeloid leukemia with minimal differentiation switching to mixed phenotype acute leukemia： one case report

目的 分析1例急性微分化型髓细胞白血病转换为不另作特定分类急性混合表型白血病的诊断过程,并探索其与其他急性微分化型髓细胞白血病和急性混合表型白血病病例的异同.方法 采用细胞涂片染色或化学染色方法对1例原发急性微分化型髓细胞白血病转换为不另作特定分类急性混合表型白血病病例进行细胞形态学分析;采用流式细胞术进行免疫表型分析;采用染色体G显带技术进行核型分析;应用RT-PCR技术进行融合基因的检测.并与2例急性微分化型髓细胞白血病和1例急性混合表型白血病进行实验室诊断结果比较,了解这一罕见的急性白血病发生转化的特征.结果 转换前急性微分化型髓细胞白血病在形态上表现为骨髓原始细胞占0.82,可见明显核仁,无Auer小体;免疫表型为造血相关抗原CD38和HLA-DR阳性,部分髓系抗原（CD13、CD56和CD11b）阳性,淋系抗原CD7阳性;其他髓系抗原（MPO、CD33和CD15）阴性,B系抗原（CD79a、CD19和CD22）阴性,T系抗原（胞内CD3、CD4和CD8）阴性.而转换后不另作特定分类急性混合表型白血病在形态上表现为骨髓原始细胞极度增生,占0.42,嗜酸粒细胞增多,嗜碱粒细胞可见;免疫表型为造血相关抗原CD38和HLA-DR阳性,髓系抗原（MPO和CD13）阳性,B系抗原（CD19和CD79a）阳性,T系抗原（胞内CD3）阳性,淋系抗原CD7阳性.对照组白血病具有典型的形态学和免疫表型特点,均未见异常染色体核型和融合基因.结论 该病例诊断复杂,临床少见,综合分析急性微分化型髓细胞白血病和不另作特定分类急性混合表型白血病的实验室特征对确诊十分重要,而免疫表型的变化是关键.

Objective To analyze the diagnostic process of a rare case of acute myeloid leukemia with minimal differentiation undergoing a lineage switch to mixed phenotype acute leukemia, NOS-rare types,and to investigate its difference from other acute myeloid leukemia and mixed phenotype acute leukemia. Methods Following tests were performed on the patient with switched mixed phenotype acute leukemia and three control leukemia patients （ including two acute myeloid leukemia with minimal differentiation and one mixed phenotype acute leukemia ）. Cell morphology was analyzed by bone marrow smear and related cell chemical staining. Immunophenotyping of bone marrow was performed by flow cytometry （ FCM ）. G-banding technique was used for karyotype analysis and RT-PCR was used for fusion gene detection. All the laboratory data of the switched patient were compared to that of three control patients in order to reveal the characteristics of such a rare phenotype switch in acute leukemia. Results Before switching, the morphology of acute myeloid leukemia with minimal differentiation demonstrated 0.82 blasts occurring in bone marrow, distinct nucleoli and absence of Auer rods. Blast cells expressed hematopoieticassociated antigens （ CD38, HLA-DR ）, myeloid antigens （ CD13, CD56, CD11b ） and CD7. And these blasts were negative for MPO, CD33, CD15, CD79, CD19, CD22, cytoplasmic CD3, CD4 and CD8. After switching, 0. 42 blasts were found in bone marrow, showed eosinophilia and presence of basophile. Blast cells expressed hematopoietic-associated antigens （ CD38, HLA-DR ）, myeloid antigens （ MPO, CD13 ）,lymphoid antigens （ CD19, CD79a ,cytoplasmic CD3, and CD7 ）. The control group showed typical morphology and immunophenotyping. No abnormal karyotype and fusion gene were detected. Conclusions It is a rare and complicated case that acute myeloid leukemia with minimal differentiation switched to mixed phenotype acute leukemia, NOS-rare types. The laboratory features, especially the change of immunophenotyping play an important role in the diagnosis.