目的：探讨眼眶原发性滑膜肉瘤(synovial sarcoma，SS)的临床病理学及分子遗传学特点。方法：收集1例复旦大学附属眼耳鼻喉科医院眼科2020年10月收治并经病理学检查证实为眼眶原发性SS的病例，同时回顾性分析文献中已报道的10例眼眶原发性SS的临床及病理检查资料，包括临床表现、影像学检查、组织学特点、免疫表型及分子病理学检查结果。结果：患者女，53岁，因“复发性右眼眶内肿物13余年”收治入院。SS组织病理学：肿瘤由弥漫分布的单一短梭形细胞组成，肿瘤细胞异型性明显，胞质少，核分裂多见；肿瘤侵犯结膜下、巩膜表面、视神经鞘膜、眶内肌肉及纤维脂肪组织。免疫组织化学检查提示波形蛋白(Vimentin)、Calpolnin、CD99、Bcl-2均阳，SMARCB1(INI-1)部分阳/弱阳。荧光原位杂交(fluorescence in situ hybridization，FISH)法检测到SS18基因易位。回顾性总结文献中已报道的10例和本例(总共11例)眼眶SS患者，其中男性2例，女性9例，左眼6例，右眼5例；患者发病年龄为1~53岁，平均年龄22岁，中位年龄24岁。患者术前病程范围较广，为1周~13年。11例中，5例症状至少出现3年以上，多表现为进行性眼球突出伴眼球移位及运动受限，疼痛及视力下降。CT和MRI上多表现为分叶状或者卵圆形软组织肿块，部分因出血坏死出现囊性外观，增强扫描显示病灶呈不均匀强化。组织学上，本组11例眼眶SS中单相纤维型7例，双相型4例，单相纤维型中有2例存在分化差的成分。免疫组织化学染色显示：上皮样成分表达上皮标记(CKpan、CK7、CK19)和Vimentin；梭形细胞表达Vimentin、CD99、Bcl-2、Calpolnin、TLE1及灶性表达上皮标记。结论：眼眶原发性滑膜肉瘤罕见，形态上需要和眼眶其他软组织来源恶性肿瘤相鉴别，其具有特征性t(x:18)(p11;q11)染色体易位，产生SY T-SSX融合基因，分子病理学的检测有助于最后确诊。

Objective: To investigate the clinicopathological and molecular genetics features of synovial sarcoma (SS) of the orbit. Methods: We retrospectively reviewed 10 published cases of primary SS of the orbit, along with 1 case of primary SS of the orbit confirmed by pathology who was admitted to the ophthalmology department of Eye & ENT Hospital of Fudan University in October 2020. The clinical data, radiological findings,morphology, immunophenotype and genetic characteristics of the cases were analyzed. Results: Our case was a 53-year-old woman with an SS in the right orbit, which had recurred multiple times. Histopathologic examination showed a primitive tumor composed of spindled and ovoid cells. Focal infiltration was observed in adjacent structures, such as the sub-conjunctiva, scleral surface, optic nerve sheath, muscle, and fibro-fatty tissue. Immunohistochemistry showed positivity for vimentin, calponin, CD99, and Bcl-2 and loss of INI-1expression, which is typical of SS. Fluorescence in situ hybridization (FISH) showed the (X;18)translocation in the tumor cells. The analysis included 2 males and 9 females aged between 1 and 53 years old (mean: 22 years; median: 24 years). Among the SS cases, 6 left eyes and 5 right eyes (all monocular cases)were affected. Symptoms had been present from 1 week to 13 years in the case from our hospital, while in 5 cases, symptoms had been present for at least 3 years. Common clinical features of the patients included proptosis or globe displacement, decreased vision, and pain. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed an ovoid mass with heterogenous enhancement and a cystic appearance,which was probably attributable to hemorrhage or necrosis. Of these 11 cases, 7 cases were biphasic SS,4 were monophasic fibrous SS, and 2 were poorly differentiated in monophasic SS. Immunohistochemistry revealed positivity for pan-cytokeratin (CKpan), CK7, CK19, vimentin, cluster of differentiation 99 (CD99),B-cell lymphoma 2 (Bcl-2), calponin and transducin-like enhancer protein 1 (TLE1). Conclusion: Primary SS of the orbit is extremely rare and needs to be distinguished from other spindle cell tumors of orbital soft tissue. The SS diagnosis is based on the presence of the t(X;18) (p11; q11) translocation, which results in an SYT-SSX fusion gene.