Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, St. Louis, MO, 63110, USA.
Skeletal Radiol. 2013 Jun;42(6):859-67. doi: 10.1007/s00256-013-1589-4. Epub 2013 Mar 1.
A case of right knee intra-articular synovial sarcoma in a 26-year-old man is reported. The patient had experienced 12 to 18 months of chronic posterior right knee pain with flexion contracture of the leg. Magnetic resonance imaging (MRI) examination demonstrated nonspecific characteristics of a well-circumscribed, homogeneous mass within the posterior lateral compartment of the knee joint. The mass was isointense and hyperintense to muscle on T1- and T2-weighted sequences respectively, and initially clinically diagnosed as a localized tenosynovial giant cell tumor. However, histological examination showed the lesion to be a synovial sarcoma arising from the synovium of the knee joint. Synovial sarcoma may have a nonspecific MR appearance, especially when less than 5 cm in size, often simulating a less aggressive process. Primary intra-articular origin may predispose to earlier presentation, and therefore, radiological evaluation of smaller masses. Nonspecific MR characteristics of small, intra-articular masses provide a diagnostic dilemma. Synovial sarcoma should be considered in the differential diagnosis when distinguishing MR characteristics of other common joint-centered entities are not present.
报告了一例 26 岁男性右膝关节内滑膜肉瘤病例。该患者经历了 12 至 18 个月的慢性右膝后疼痛，伴有腿部屈曲挛缩。磁共振成像（MRI）检查显示膝关节后外侧间隔内有界限清楚、均匀的肿块，具有非特异性特征。肿块在 T1 和 T2 加权序列上与肌肉等信号强度和高信号强度，最初临床诊断为局限性腱鞘巨细胞瘤。然而，组织学检查显示病变为源自膝关节滑膜的滑膜肉瘤。滑膜肉瘤的 MRI 表现可能不具有特异性，尤其是在小于 5 厘米时，常模拟侵袭性较低的过程。原发性关节内起源可能导致更早出现，因此，对较小肿块进行放射学评估。小的关节内肿块的非特异性 MRI 特征提供了诊断上的困境。当其他常见的以关节为中心的实体缺乏 MRI 特征时，应考虑滑膜肉瘤作为鉴别诊断。
