Abstract：
Synovial sarcoma (SS) and solitary fibrous tumor (SFT) are entities with considerable morphological and immunohistochemical similarities that sometimes show a non-confirmatory profile (TLE1 negative, CD34 and focal or negative STAT6 and lack of specific fusion IHC markers), in which the utility ultrastructure is unknown. A cross-sectional, retrospective, analytical, nonexperimental study was carried out by the Department of Pathology of the National Cancer Institute of Mexico (INCan) e from January 1, 2009 to December 31, 2018. With 17 SFT cases with diffuse or focal CD34 and STAT6 positivity and 18 cases of SS with positive FISH molecular test t(X:18) breakapart were studied by electron microscopy of fresh glutaraldehyde fixed or paraffin-embedded tissue. The ultrastructural findings with a significant difference present in the SS were tandem tight junctions, desmosomes and abundance of dilated rough endoplasmic reticulum (RER) cisternae (p < 0.001, 0.003, and 0.001, respectively); while in the (SFT) the presence of abundant glycogen, basal lamina, long and slender cytoplasmic processes, pinocytic vesicles, hemidesmosomes, and/or dense plaques, collagen skein, and microvilli-like buds (p = 0.028, 0.005, and <0.001 for the last five). We then infer that the five distinctive markers of the SFT are the collagen skeins intermingled with cellular processes in a shape of \"squid can,\" and the pinocytic vesicles as they were not observed in any case of SS. Conversely, tandem junctions were not found in any SFT case. Although the presence of multivesicular buds in the SFT was not significant, it had not been previously described.
摘要：
滑膜肉瘤（SS）和孤立性纤维瘤（SFT）是具有相当大的形态学和免疫组织化学相似性的实体，有时显示出非确证性特征（TLE1阴性，CD34和局灶性或阴性STAT6，缺乏特异性融合IHC标记），其中公用事业超微结构是未知的。横截面，回顾性,分析，非实验研究由墨西哥国家癌症研究所(INCan)病理学系于2009年1月1日至2018年12月31日进行.通过新鲜戊二醛固定或石蜡包埋组织的电子显微镜研究了17例弥漫性或局灶性CD34和STAT6阳性的SFT和18例FISH分子测试t（X：18）破裂的SS。在SS中存在显着差异的超微结构发现是串联紧密连接，桥粒和扩张的粗面内质网（RER）池的丰度（分别为p<0.001、0.003和0.001）；而在（SFT）中存在丰富的糖原，基底层，细长的细胞质过程，胞囊泡，半染色体，和/或致密斑块，胶原蛋白绞丝，和微绒毛样芽（最后五个p=0.028、0.005和<0.001）。然后我们推断，SFT的五个独特标记是胶原蛋白绞链与细胞过程混合在一起，呈鱿鱼罐的形状，“和在任何情况下都没有观察到的血小板囊泡。相反，在任何SFT病例中均未发现串联连接。尽管SFT中多囊芽的存在并不显著，以前没有描述过。
