同时发生的双系造血恶性肿瘤罕见；然而，已有报道多例急性髓系白血病（AML）和T淋巴母细胞淋巴瘤（T-LBL）的同时发生。针对同时出现AML和T-LBL的标准治疗尚未确立，且其预后非常糟糕。需要进一步研究以制定标准治疗方案，提高患者的生存率。 一名69岁男性因胸痛而前往急诊室就诊。计算机断层扫描显示颈部和腹股沟多发肿大淋巴结和肺动脉栓塞伴肺梗塞。此外，由于白细胞增多，进行外周血涂片检查发现循环中有原始造血细胞。通过骨髓检查诊断为急性髓单核白血病（AMML），通过颈部淋巴结活检证实存在T-LBL，终末脱氧核苷酸转移酶、簇抗原（CD）34和CD4呈阳性。由于患者病情较差，无法接受强化化疗，故予以脱氧胞苷和地塞米松治疗。经过4个周期的脱氧胞苷加地塞米松治疗，AML和T-LBL均达到完全缓解。 我们报告了脱氧胞苷，一种去甲基化剂在伴有双系造血恶性肿瘤的患者中的治疗效果，并建议进一步研究以评估去甲基化剂对淋巴系和双系造血恶性肿瘤的治疗效果。©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.

Simultaneous bilineage hematologic malignancies are rare; however, several cases of acute myeloid leukemia (AML) and T-lymphoblastic lymphoma (T-LBL) co-occurrence have been reported. A standard treatment for simultaneous AML and T-LBL has not yet been established, and its prognosis is very poor. Further studies to develop standard treatments are required to increase patient survival rates.A 69-year-old man complaining of pleuritic chest pain visited the emergency room. Computed tomography revealed multiple enlarged lymph nodes (LNs) in the neck and groin and pulmonary thromboembolism with pulmonary infarction. Furthermore, a peripheral blood smear performed due to leukocytosis revealed circulating blasts. Acute myelomonocytic leukemia (AMML) was diagnosed after bone marrow examination, and T-LBL positivity for terminal deoxynucleotidyl transferase, cluster of differentiation (CD)34, and CD4 was confirmed by cervical LN biopsy. Decitabine and dexamethasone were administered because he could not receive intensive chemotherapy due to poor performance status. Complete remission of AMML and T-LBL was achieved after 4 cycles of decitabine plus dexamethasone.We report the therapeutic effect of decitabine, a hypomethylating agent (HMA), in patients with concurrent bilineage hematologic malignancies and suggest that further studies are required to evaluate the therapeutic effect of HMAs on both lymphoid and bilineage hematologic malignancies.©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.