摘要目的 探讨胸腺原发黏膜相关淋巴组织(MALT)结外边缘区B细胞淋巴瘤的临床病理特征.方法 对3例经于术切除、病理证实的胸腺原发MALT淋巴瘤病例进行临床病理分析,并复习文献,讨论其临床、病理特征、治疗和预后.结果 3例胸腺MALT淋巴瘤,男性1例、女性2例,年龄分别为36、35、41岁,均与Sj(o)gren综合征相关,1例伴有B组症状.肉眼观察肿瘤呈饼状,边界清楚,切面囊实性,囊腔数量不等.显微镜下观察3例,低倍镜下均见囊腔形成,弥漫浸润的淋巴组织和残存的胸腺小体,可见反应性淋巴滤泡,高倍镜下见肿瘤细胞为中心细胞样细胞,部分胞质丰富并且透亮,似单核样B细胞,浸润胸腺小体或致胸腺小体扩张或浸润囊腔衬覆上皮,形成特征性的淋巴上皮病变.3例均见明显的浆细胞分化.瘤细胞均呈CD20、CD79a、bcl-2阳性表达,浆细胞呈Kappa轻链限制性表达,CD43、CD5、CD23、cyclin D1、CD10、bcl-6和Lambda均呈阴性表达.反应性T细胞呈CD3、CD5、CD43阳性、TdT阴性表达.残存胸腺小体和囊腔衬覆上皮CK19阳性.3例经PCR检查提示IgH重排.3例临床分期分别为Ann Arbor Ⅰ、Ⅱ期,均行肿物切除术,3例行规范化疗(1例化疗中)、2例行放疗,达完全缓解,分别随访24、18、3个月无复发.结论 熟悉并掌握胸腺原发MALT淋巴瘤特点有利于通过常规HE染色和免疫组织化学染色明确诊断.该瘤需要与胸腺淋巴组织反应性增生、胸腺其他类型淋巴瘤和胸腺瘤鉴别诊断.

abstractsObjective To study the clinicopathologic features of primary thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT). Methods The clinical and pathologic findings were evaluated in 3 cases of biopsy confirmed thymic MALT lymphoma. The clincopathologic features,treatment and prognosis were discussed and literatures reviewed.Results One male and two female patients presented with asymptomatic mediastinal masses with a history of Sj(o)gren syndrome.They were aged 36,35 and 41 years respectively,and only one patient had B symptoms.Grossly,all three tumors were encapsulated and had multiple variable-sized cysts on cut-surface.Histopathologically,the normal thymic lobular architecture was effaced by abnormal dense lymphoid infiltration. Prominent lymphoepithelial lesions were formed by centrocyte-like cells infiltrating and expanding Hassall's corpuscles and epithelial cyst lining. All cases showed apparent plasmacytic differentiation.Immunhistochemically,the tumor cells were positive for CD20,CD79a,bcl-2 and negative for CD3,CD5,cyclin D1,CD43,CD10,bcl-6,and CD23.The plasma cells showed kappa light chain restriction.Immunoglobulin heavy chain rearrangement in three cases was confirmed by PCR.All patients were at early stage and received routine chemotherapy with or without radiothcrapy aftcr surgical rcmoval.All patients achieved complete remission with 24,18 and 3 months follow-up,respectively. Conclusions Primary thymic MALT lymphoma may be a rare distinctive lymphoma. It can be diagnosed by HE and immunohistochemical study and should be differentiated from reactive lymphoid proliferation,other types of lymphoma and mediastinal thymoma.