颞颌关节的软骨肉瘤和滑膜软骨病有着类似的临床和组织病理学特征。我们旨在找到能够区分颞颌关节软骨肉瘤和滑膜软骨病的CT和MR成像特征。对12例经组织病理学证实为颞颌关节软骨肉瘤和35例滑膜软骨病的患者的CT和MR图像进行了回顾性评估。评估的成像特征包括病变大小、病变中心、强化、周围骨破坏/硬化、浸润到外翼肌腱、钙化、骨膜反应和骨赘形成。对颞颌关节软骨肉瘤和滑膜软骨病进行了比较，对于定量变量，使用学生t检验进行统计，对于定性变量，使用Fisher确切检验或线性协变量关联测试。进行了接收者操作特征曲线分析，确定根据9个成像特征的组合得到的综合评分来区分颞颌关节软骨肉瘤和滑膜软骨病的诊断性能。 颞颌关节软骨肉瘤的高危成像特征包括以下内容：病变位于下颌骨髁状突中心，下颌骨髁状突破坏，关节凹/关节臼无破坏/硬化，浸润到外翼肌腱，无或斑点状钙化，骨膜反应，内部强化，大小≥30.5 mm。用于区分颞颌关节软骨肉瘤和滑膜软骨病的最佳截断值是存在任何4个高危成像特征，曲线下面积为0.986，准确度为95.8%。 CT和MR成像特征可以区分颞颌关节软骨肉瘤和滑膜软骨病，当使用9个成像特征的子组合时，其诊断性能得到改进。 本文为《美国神经放射学杂志》2023年版权所有。

Chondrosarcoma and synovial chondromatosis of the temporomandibular joint share overlapping clinical and histopathologic features. We aimed to identify CT and MR imaging features to differentiate chondrosarcoma from synovial chondromatosis of the temporomandibular joint.The CT and MR images of 12 and 35 patients with histopathologically confirmed chondrosarcoma and synovial chondromatosis of the temporomandibular joint, respectively, were retrospectively reviewed. Imaging features including lesion size, center, enhancement, destruction/sclerosis of surrounding bone, infiltration into the tendon of the lateral pterygoid muscle, calcification, periosteal reaction, and osteophyte formation were assessed. A comparison between chondrosarcoma and synovial chondromatosis was performed with a Student t test for quantitative variables and the Fisher exact test or linear-by-linear association test for qualitative variables. Receiver operating characteristic analysis was performed to determine the diagnostic performance for differentiation of chondrosarcoma and synovial chondromatosis based on a composite score obtained by assigning 1 point for each of 9 imaging features.High-risk imaging features for chondrosarcoma were the following: lesion centered on the mandibular condyle, destruction of the mandibular condyle, no destruction/sclerosis of the articular eminence/glenoid fossa, infiltration into the tendon of the lateral pterygoid muscle, absent or stippled calcification, periosteal reaction, internal enhancement, and size of ≥30.5 mm. The best cutoff value to discriminate chondrosarcoma from synovial chondromatosis was the presence of any 4 of these high-risk imaging features, with an area under the curve of 0.986 and an accuracy of 95.8%.CT and MR imaging features can distinguish chondrosarcoma from synovial chondromatosis of the temporomandibular joint with improved diagnostic performance when a subcombination of 9 imaging features is used.© 2023 by American Journal of Neuroradiology.