Billings S D, Meisner L F, Cummings O W, Tejada E
Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, USA.
Mod Pathol. 2000 Jan;13(1):68-76. doi: 10.1038/modpathol.3880011.
Two cases of synovial sarcoma that arose in the upper digestive tract are reported. One case was a polypoid mass that arose at the gastroesophageal junction; the other was a large intramural mass that arose in the wall of the stomach. Both cases had a classic biphasic pattern. In the stomach tumor, the biphasic morphology was focal and there was an abrupt transition to poorly differentiated synovial sarcoma. The tumors had immunohistochemical features that were consistent with synovial sarcoma. Ultrastructural evaluation of the gastroesophageal tumor supported the diagnosis. The diagnostic X;18 translocation was demonstrated by fluorescence in situ hybridization on sections from paraffin-embedded tissue in 86% and 50% of interphase nuclei from the gastroesophageal and gastric tumor, respectively. The translocation was present in equal frequency in the epithelial and spindle cells in the biphasic areas and the poorly differentiated areas of the gastric tumor, indicating that the development of the more aggressive subclone was probably due to genetic mutations not encompassing the SYT-SSX gene fusion product. We are aware of only five reported cases of synovial sarcoma arising in the digestive tract, all in the proximal esophagus. These cases are the first reported arising in the gastroesophageal junction and stomach and the only cases of synovial sarcoma of the digestive tract in which the diagnostic translocation was demonstrated. Sarcomatoid carcinoma (carcinosarcoma) and gastrointestinal stromal tumor are the main differential diagnoses for synovial sarcoma in this site. Synovial sarcoma of the digestive tract may be underdiagnosed, and its recognition may have important clinical implications. Fluorescence in situ hybridization is helpful in making this distinction.
本文报告了2例发生于上消化道的滑膜肉瘤。1例为发生于胃食管交界处的息肉样肿物；另1例为发生于胃壁的较大壁内肿物。2例均具有典型的双相性结构。胃肿瘤中，双相性形态为局灶性，且突然转变为低分化滑膜肉瘤。肿瘤具有与滑膜肉瘤一致的免疫组化特征。胃食管肿瘤的超微结构评估支持该诊断。通过荧光原位杂交在石蜡包埋组织切片上检测到，胃食管肿瘤和胃肿瘤分别有86%和50%的间期核显示出诊断性的X;18易位。在胃肿瘤的双相性区域和低分化区域的上皮细胞和梭形细胞中，易位出现的频率相同，这表明侵袭性更强的亚克隆的发展可能是由于不涉及SYT-SSX基因融合产物的基因突变所致。我们仅知晓5例报道的发生于消化道的滑膜肉瘤病例，均位于食管近端。这些病例是首次报道发生于胃食管交界处和胃的病例，也是仅有的在消化道滑膜肉瘤中证实有诊断性易位的病例。肉瘤样癌（癌肉瘤）和胃肠道间质瘤是该部位滑膜肉瘤的主要鉴别诊断。消化道滑膜肉瘤可能诊断不足，对其的认识可能具有重要的临床意义。荧光原位杂交有助于进行这种鉴别。
