膝关节色素沉着绒毛结节性滑膜炎的影像学诊断

目的 探讨膝关节色素沉着绒毛结节性滑膜炎(PVNS)的影像学表现。方法 回顾分析9例经手术及病理证实的色素沉着绒毛结节性滑膜炎影像学资料并进行总结。9例膝关节病变均行MR检查，其中3例增强扫描；X线平片检查6例；CT平扫5例。结果 (1)X线表现：6例中关节间隙5例正常，1例增宽；股骨髁破坏1例；胫骨平台破坏4例；共9个病灶，其中7个病灶周围见硬化环。(2)CT表现：5例PVNS均显示关节腔积液；股骨髁合并胫骨平台破坏1例，胫骨平台单发或多发破坏4例，共12个病灶，所有病灶周围均见硬化环。2例合并胭窝内软组织密度肿块。(3)MRI表现：9例中弥漫型7例，局灶型2例。7例弥漫型PVNS均见关节腔积液，其中3例髌上囊积液中见低信号结节，3例前、后交叉韧带表面可见不规则增厚的低信号滑膜覆盖，6例伴有股骨髁或胫骨平台骨质破坏，共15个病灶，其中13个病灶周围绕以低信号硬化环。3例增强扫描显示增厚的滑膜和结节均明显强化。2例局灶型PVNS表现为单发性肿块伴关节腔积液。结论 膝关节色素沉着绒毛结节性滑膜炎的MRI表现较CT、X线表现具有特征性，能够作出正确诊断。

The imaging diagnosis of pigmented villonodular synovitis of knee joint

Objective To evaluate the imaging representations of pigmented villonodular synovitis (PVNS) of the knee joint. Methods Nine patients of PVNS confirmed by operation and pathology were retrospectively analyzed and summarized. All patients were examined by MRI, and 3 of them received contrast enhanced MRI. Plain film and CT were performed in 6 and 5 cases, respectively. Results (1) Radiograph in the 6 patients displayed that intervals of the knee joint was normal in 5 patients and widened in 1 patient. Bone erosive lesions were seen in the femoral condyle in 1 patient and in the tibial plateau in 4 patients. There were totally 9 lesions, and surrounding sclerotic margins were seen in 7 lesions. (2) CT scan showed the joint effusion presented in all of the 5 patients. One patient had erosive lesions in femoral condyle and tibial plateau, and 4 patients had single or multiple lesions in tibial plateau. There were totally 12 bone erosive lesions and the sclerotic margins were presented in all lesions. Two patients had the soft tissue mass within popliteal fossa. (3) MRI in 9 patients showed diffuse form (7 cases) and localized form (2 cases). In diffuse form of PVNS, the joint effusion presented in all of the patients, and low signal nodules were displayed in the suprapatellar bursa effusion in 3 patients, and low signal proliferated synovium covered on the surface of the cruciated ligaments in 3 patients on T 2WI. There were totally 15 bone erosive lesions in femoral condyle and in tibial plateau in 6 patients, and the low signal sclerotic margins were showed in 13 lesions. The proliferated synovium and synovial nodules were enhanced after contrast administration in 3 patients. In localized form of PVNS in 2 patients, the single mass with joint effusion occurred. Conclusion The MRI finding of PVNS is characteristic. The diagnosis of PVNS can be correctly established based on MRI features.