伴有淋巴样间质的微结节型胸腺瘤临床病理特征及文献复习

Clinicopathological features and literature review of micronodular thymoma with lymphoid stroma

目的探讨伴有淋巴样间质的微结节型胸腺瘤(MNT)的临床病理特点、生物学行为、免疫表型、鉴别诊断及其来源。方法收集重庆医科大学分子医学检测中心已手术治疗的MNT 2例,对其临床症状、病理特征、免疫表型、临床治疗及预后进行回顾性研究并进行相关文献复习。结果男女各1例,年龄分别为73、70岁。肿瘤大小分别为2.50 cm×2.50 cm×2.00 cm及1.20 cm×0.70 cm×0.50 cm,边界清楚,切面呈实性,灰白色,质地中等。镜检显示肿瘤主要由温和的上皮样细胞及淋巴细胞组成,上皮细胞呈团状或岛状分布,短梭形,细胞异型性较小,细胞核仁不清楚,细胞核分裂罕见,其间被淋巴细胞间隔,局灶见淋巴滤泡形成。免疫组织化学(IHC)检测显示肿瘤性上皮细胞:高分子角蛋白(CKH)、细胞角蛋白19(CK19)、CK、P63、CD57均为阳性,上皮膜抗原(EMA)、波形蛋白(Vimentin)为阴性;间质淋巴细胞:CD5、CD3主要表现为非生发中心阳性,CD20主要表现为淋巴滤泡中心阳性,Bcl-2表现为非生发中心及淋巴套区阳性,上皮结节周围及结节内少量不成熟T细胞末端脱氧核苷酸转移酶(TdT)阳性,上皮内散在细胞CD1a、S100、Langerin阳性。结论MNT是一种非常罕见的肿瘤,镜下特点比较典型,IHC检测对其诊断及鉴别诊断有非常重要的作用。

Objective To investigate the clinicopathological characteristics,biological behavior,immunophenotype and differential diagnosis of micronodular thymoma(MNT)with lymphoid stroma and to futher explore its source.Methods 2 cases of MNT with lymphoid stroma treated by Molecular Medicine Testing Center of Chongqing Medical University were collected.The clinical symptoms,pathological features,immunophenotype,clinical treatment and prognosis were retrospectively studied and related literatures were reviewing.Results 1 case of male and 1 case of female,aged 73 and 70 years old,respectively.Gross examination showed the tumor size was 2.50 cm×2.50 cm×2.00 cm and 1.00 cm×0.70 cm×0.50 cm.The boundary was clear,the cut surface was solid,grayish white,and medium texture.Microscopic examination,showed the tumor is mainly composed of mild epithelioid cells and lymphocytes.The epithelial cells are cluster-like or island-like,short fusiform,with small cell atypia,unclear nucleoli,and rare nuclear division,separated by lymphocytes,localized lymphoid follicle formation.Immunohistochemistry(IHC)showed that neoplastic epithelial cells were positive for CKH,CK19,CK,P63,CD57,negative for EMA and Vimentin.CD5 and CD3 is mainly positive for non-germinal center in interstitial lymphocytes.CD20 is mainly positive for lymphoid follicle center,Bcl-2 is positive in non-germinal center and lymphatic zone,and TdT is positive for a few immature T cells around epithelial nodules and in nodules.The scattered cells in the epithelium CD1a,S100,Langerin positive.Conclusion MNT is a very rare tumor with typical microscopic features.IHC plays an important role in the diagnosis and differential diagnosis.