Objective: To explore the key points of the pathological and differential diagnoses of extra-medullary masses of hematopoietic cell tumors of ambiguous lineage, and to discuss the possible solutions. Methods: Five hematopoietic cell tumors of ambiguous lineage cases were collected, including myeloid sarcoma, mixed phenotype acute leukemia, B/myeloid, T-lymphoblastic lymphoma combined with acute myeloid leukemia, acute undifferentiated leukemia with cutaneous MPDCP and early T-precursor cell acute lymphoblastic leukemia. The data including morphology, immunostaining, and flow cytometry analysis were collected, and we explored the problems and differential diagnosis in the diagnosis of hematopoietic cell tumors of ambiguous lineage. Results: The five cases showed that the accurate pathological diagnosis and classification of hematopoietic cell tumors of ambiguous lineage should be based on lineage-specific antigens. Moreover, tumor cells have the potential of multi-directional differentiation. In different sites or different periods, the differentiation of tumor cells may be different. Biopsy and detection of all related markers should be performed for the initial diagnosis, and the detection should be repeated when the condition of the patient changes. Combined application of multi-techniques, including morphology and flow cytometry analysis, is recommend for the diagnosis of hematopoietic cell tumors of ambiguous lineage, since the conventional morphology and immunophenotyping methods are limited. Conclusion: Hematopoietic cell tumors of ambiguous lineage are derived from hematopoietic stem cells with a potential of multi-differentiation. The differentiation of tumor cells is variable. We need to integrate cell morphology, flow cytometry, pathology, clinical data, and molecular genetics to make a comprehensive diagnosis.
目的： 探究系别不确定的造血细胞肿瘤髓外肿块病理诊断与鉴别诊断要点，并提出诊断的建议。 方法： 选取较常见的5例系别不确定的造血细胞肿瘤，分别为髓系肉瘤、混合表型急性白血病，B/髓系、T淋巴母细胞淋巴瘤合并急性髓系白血病、急性未分化白血病合并皮肤成熟浆样树突细胞增殖及早期前驱T细胞急性淋巴细胞白血病，收集其形态学、免疫组化检测、流式细胞术结果，探究系别不确定的造血细胞肿瘤诊断中存在的问题及鉴别诊断。 结果： 5个病例提示系别不确定的造血细胞肿瘤准确的病理诊断和分型需要：①基于系别特异性标志物；②系别不确定的造血细胞肿瘤细胞具有多向分化潜能，不同部位或不同时期肿瘤细胞分化方向有所不同，初诊及病情变化时需多次活检并全面标记各系相关标志物以协助诊断；③常规病理形态学及组织的免疫表型检测在诊断系别不确定的造血细胞肿瘤时存在局限性，需要结合形态学、流式细胞术检查等综合分析。 结论： 系别不确定的造血细胞肿瘤来源于具有多向分化潜能的造血干细胞，肿瘤细胞分化存在多样性，需要结合细胞形态学、流式细胞术、病理检查、临床特征、分子遗传学等进行诊断。.
Keywords: Cell lineage; Leukemia, biphenotypic, acute; Precursor cell lymphoblastic leukemia-lymphoma.