下肢软组织滑膜肉瘤的MRI特征

MR Imaging Features of Soft Tissue Synovial Sarcoma of Lower Extremity

目的：探讨下肢软组织滑膜肉瘤MRI特征。方法：回顾性分析经病理确诊的15例（男11例,女4例;年龄18-64岁,平均32.8岁）下肢软组织滑膜肉瘤的MRI表现,采用1.5T超导磁共振成像仪,均行平扫加增强检查。结果：肿瘤均表现为位置较深的梭形或分叶状软组织肿块,最大直径4.8-16.5cm;邻近关节12例,远离关节3例,5例包绕邻近关节或骨质生长,2例侵犯邻近骨质。T1WI上与肌肉呈等信号为主,其中6例肿块可见斑片状稍高信号区,4例肿块可见斑点状低信号;T2WI上表现为以高或稍高信号为主的混杂信号,6例出现高、中、低＂三重信号＂;7例肿瘤内可见低信号分隔征,5例瘤周可见水肿,5例瘤周可见不完整假包膜。增强扫描肿块均呈明显不均匀强化,分隔强化2例,瘤周水肿强化1例。结论：下肢软组织滑膜肉瘤的MRI表现具有一定的特征,特别是肿瘤邻近关节生长,瘤内有分隔、＂三重信号＂征及不均匀强化具有重要诊断价值。

Purpose： To investigate the MR imaging features of soft tissue synovial sarcoma of lower extremity. Methods： MR Imaging findings of 15 cases soft tissue synovial sarcoma of lower extremity proved by pathology results were analyzed retrospectively. All the cases were undergone MRI plain scans and enhanced scans.Results： Tumors were characterized by fusiform or lobulated masses which located at deep position and had a largest diameter from 4.8cm to 16.5 cm. There were 12 cases located adjacent to the joints,and 3 cases located far away from the joints,5 of them grew surrounding the adjacent joint or bone and 2 of them invaded adjacent bones. On T1 WI,the signal intensity of the tumors were similar to the muscle,except 6 cases were with patchy slightly high intensity signal and 4 cases with mottled low intensity signal. On T2 WI,the tumors were characterized by high or slightly high mixed intensity signals,except 6 cases with high,medium and low intensity mixed signals. In term of tumor feature,7 of them had septum,5 of them had edema and 4 of them had incomplete psuedocapsule. On MRI enhancement scanning,the tumors were obvious uneven enhanced. Conclusion：MRI of soft tissue synovial sarcoma of lower extremity has certain characteristics. Features of tumor adjacent to the joint with septum,with ＂triple＂ intensity signal and non-uniform enhancement have important diagnostic value.