目的 探讨髓系肉瘤（myeloid sarcoma，MS）患者的临床特征及预后。方法 回顾性分析2016年12月至2022年1月间我科连续诊治的20例MS患者的临床资料及骨髓、血液学相关检测结果，总结临床资料，并比较3种类型MS患者[孤立型MS、MS合并髓内病变、急性髓系白血病（acute myeloid leukemia， AML）治疗后继发MS]的预后。结果 20例MS患者中，男10例，女10例；中位年龄为37（6～62）岁；发病部位鼻咽最常见（25%），其次为纵隔、胸椎、淋巴结、乳腺（各占10%），再次为子宫颈、眼部、脾脏、睾丸、腹部、骶尾部、幽门（各占5%）；孤立型MS 10例，MS合并髓内病变6例，AML治疗后继发MS 4例。免疫组化阳性率由高到底分别为CD99（100%）、CD43（95%）、MPO（95%）、BCL-2（90%）、CD68（75%）、CD117（50%）、CD34（45%），TdT、CD3、CD20、PAX-5均阴性。17例患者行融合基因检测，7例结果为阳性（7/17），其中3例为AML1-ETO（3/17），2例为CBFβ-MYH11(2/17)，1例为MLL-AF10(1/17)，1例为BCR/ABL1(1/17)；17例患者行染色体核型分析，其中6例发现染色体核型异常（6/17）；4例患者行荧光原位杂交（fluorescence in situ hybridization，FISH）检查，其中3例结果为阳性（3/4）;10例患者行基因突变检查，9例结果为阳性（9/10），其中CEBPA基因突变检出率最高，为5例，其次是NRAS、FLT3、NPM1和KIT，各2例。随访1～38个月，20例MS患者中7例死亡，13例生存。所有患者1年、2年、3年的累积存活率分别为75%、70%、65%。孤立型MS、MS合并髓内病变、AML治疗后继发MS患者间的生存状态没有差异（P=0.718）。结论 MS发病部位广泛，病理免疫组化标志物CD43、CD99、CD68、MPO、CD34及CD117检测对其诊断非常重要，骨髓血液学检查结果可为其靶向治疗提供依据。3种类型的MS患者生存状态没有差异，均应进行全身治疗。

Objective To investigate the clinical features and prognosis of myeloid sarcoma (MS). Methods A retrospective analysis was conducted on the clinical data and bone marrow hematological test results of 20 MS patients diagnosed and treated in our department from December 2016 to January 2022. Clinical data were summarized, and the prognosis of three types of MS patients (isolated MS, MS with intramedullary lesions, and secondary MS after AML treatment) was analyzed. Results Among the 20 MS patients, 10 were male and 10 were female. The median age was 37 years (range: 6-62). The most common site of MS was the nasopharynx (25%), followed by the mediastinum (10%), thoracic vertebrae (10%), lymph nodes (10%), breast (10%), cervix (5%), eyes (5%), spleen (5%), testes (5%), abdomen (5%), sacrococcygeal region (5%), and pylorus (5%). There were 10 cases of isolated MS, 6 cases of MS with intramedullary lesions, and 4 cases of secondary MS after AML treatment. Immunohistochemical positive rates, from high to low, were CD99 (100%), CD43 (95%), MPO (95%), BCL-2 (90%), CD68 (75%), CD117 (50%), and CD34 (45%). TdT, CD3, CD20, and PAX-5 were all negative. Fusion gene testing was performed on 17 patients, with 7 positive results (7/17), including 3 cases of AML1-ETO (3/17), 2 cases of CBFβ-MYH11 (2/17), 1 case of MLL-AF10 (1/17), and 1 case of BCR/ABL1 (1/17). Chromosomal karyotype analysis was performed on 17 patients, and 6 showed abnormal karyotypes (6/17). Fluorescence in situ hybridization (FISH) was performed on 4 patients, with 3 positive results (3/4). Genetic mutation testing was conducted on 10 patients, with 9 positive results (9/10). The most frequent mutation was CEBPA (5 cases), followed by NRAS, FLT3, NPM1, and KIT (2 cases each). During the follow-up period of 1-38 months, 7 of the 20 MS patients died, and 13 survived. The cumulative survival rates at 1, 2, and 3 years were 75%, 70%, and 65%, respectively. No statistically significant difference in survival was observed among isolated MS, MS with intramedullary lesions, and secondary MS after AML treatment (P=0.718). Conclusion MS can occur in a wide range of anatomical sites. Pathological immunohistochemical markers, including CD43, CD99, CD68, MPO, CD34, and CD117, are critical for its diagnosis. Bone marrow hematological examination results can provide a basis for targeted therapy. There is no survival difference among the three types of MS patients, and systemic treatment is recommended for all patients.