目的:提高对惰性套细胞淋巴瘤（MCL）的认识。方法:收集2013年5月南京医科大学第二附属医院就诊的1例惰性白血病期MCL患者资料。采用细胞涂片方法进行细胞形态学分析，通过流式细胞术进行免疫表型分析，采用细胞遗传学技术进行核型分析，应用聚合酶链反应技术进行免疫球蛋白基因分析，同时进行淋巴结病理和免疫组织化学分析。结合相关文献总结惰性MCL的特征及治疗方法。结果:患者，男性，60岁，无明显临床症状，伴白血病表现，无淋巴结肿大。2008年曾因孤立性淋巴结肿大行病理活组织检查，形态学检测示小细胞型，免疫表型为κ轻链，细胞遗传学示t（11；14）异位，存在克隆性免疫球蛋白基因重排，Ki-67阳性指数低。回顾性病理诊断为原位MCL。结论:惰性MCL少见，特征为无临床症状，无或轻度淋巴结肿大，惰性进展，常伴白血病表现，免疫表型轻链表达以κ为主，无复杂核型，形态学为经典或小细胞型，Ki-67阳性指数<10%，病理检查可见原位肿瘤，IgVH基因突变阳性和SOX11阴性多见。不适合用MCL国际预后指数对惰性白血病期MCL进行预后分析，应采取观察和等待、待疾病进展后再行治疗的策略。“,”Objective:To improve the understanding of indolent mantle cell lymphoma (MCL).Methods:The data of a patient with indolent leukemic MCL in the Second Affiliated Hospital of Nanjing Medical University in May 2013 were collected. The cell morphology was analyzed by using cell smear, the flow cytometry was used to make immunophenotype analysis, the karyotype analysis was performed by usig cytogenetic technique, and polymerase chain reaction (PCR) was used to make the immunoglobulin gene analysis. At the same time, lymph node pathology and immunohistochemistry were also analyzed. The related articles published were reviewed to sum up the characteristics and the treatment of indolent MCL.Results:The male patient aged 60 years was obviously asymptomatic accompanied with slow disease progression, leukemic manifestation and without lymphadenopathy. He received pathological biopsy because of located lymphadenopathy in 2008. Small cell morphology, Kappa light chain immunophenotype, t(11;14) translocation showed after the cytogenetic examination, clonal immune globulin gene rearrangement and low Ki-67 positive index were identified. In situ MCL was diagnosed by retrospective pathology.Conclusions:Indolent MCL is extremely rare. It is typically asymptomatic with none or minimal nodal involvement, indolent disease course, leukemic phase with mild lymphocytosis, Kappa light chain expression, simple karyotype, classical or small cell morphology of tumor cells and the positive index of Ki-67 <10%. In situ MCL can be seen in pathology examination. IgVH gene mutation positive and SOX11 negative expression are notable in indolent MCL. International prognostic index of MCL is probably not appropriate in the prognostic analysis of leukemic indolent MCL. It is emphasized that initial observation and having therapies only after the disease progression can be suited for indolent MCL.