结外滤泡树突细胞肉瘤四例临床病理分析

 目的　探讨并分析结外滤泡树突细胞肉瘤（FDCS）的临床病理特征。方法　应用组织学、免疫组织化学（EnVision）及EBV原位杂交检测技术，对4例FDCS进行临床和组织病理学分析，并结合文献进行探讨。结果　镜下观察肿瘤细胞呈梭形、卵圆形，胞质丰富淡染、颗粒状，核呈泡状、有清晰的小核仁，排列呈束状，席纹状及漩涡状，瘤细胞间穿行大量的小淋巴细胞并有小淋巴细胞围绕小血管形成血管周围套现象，散在多核巨细胞，病理性核分裂少见。肿瘤细胞特异性表达一个或多个树突细胞标志CD21、CD23和CD35，CD68、Vimentin、LCA和S-100表达不定，CD20、CD3和CD1a阴性，Ki-67指数10 ％～20 %，EBV原位杂交阴性。结论　FDCS是罕见的低度恶性肿瘤，有一定的特征性，确诊需要结合病理形态和免疫表型，应与胃肠道间质瘤、炎性假瘤、指突树突细胞肉瘤、恶性纤维组织细胞瘤、弥漫性大B细胞淋巴瘤、未分化癌、恶性黑色素细胞瘤等鉴别。

Clinicopathologic analysis of four cases of extranodal follicular dendritic cell sarcoma

Objective To study the clinicopathoiogic features of four cases of extranodal follicular dendritic cell sarcoma(FDCS). Methods Four cases of FDCS were examined by histological and immunohistochemistry and in situ hybridization for Epstein-Barr virus (EBV)-encoded RNA, and the related literatures were reviewed. Results Microscopically, the neoplastic cells were spindle-shaped or ovoid with pale-stained cytoplasm, indistinct cell borders, granular chromatin, distinct small nucleoli. There were varied growth patterns in the tumour, such as fascicular, circular whorls and storiform, and abundant with intermixed small lymphocytes. There scattered multinucleated giant cells and perivascular cuffing phenomenon. There were rare mitoses. The neoplastic cells were positive for one or more of the follicular dendritic markers such as CD21, CD23 and CD35. It was variably positive for CD68, Vimentin, LCA and S-100. Staining for CD20, CD3 and CD1α were negative. Ki-67 labeling ranged from 10 %-20 %. The neoplastic cells were negative for Epstein-Barrvirus (EBV)-encoded RNA. Conclusion FDCS is a rare low-grade malignant tumor with varied growth pattern. The diagnosis should be confirmed by immunohistochemical staining. It is important to recognize its morphological characteristics to avoid confusion with other similar lesions, such as gastrointestinal stromal tumour, inflammatory pseudotumor, interdigitaing dendtritic cell sarcoma, malignant histiocytoma, lymphoepithelial carcinoma, diffuse large B-cell lymphoma, and malignant melanoma.