软骨肉瘤 (骨软骨瘤软骨帽恶变)

来源：熊猫放射病史39岁男性，腹股沟区疼痛。（A 39-year-old man with groin pain.）影像学表现髋关节正位X线片(a)显示起自股骨近端内侧小转子下方基于骨表面的病变（a surface-based lesion arising from the medial aspect of the proximal femur just below the lesser trochanter），中心致密矿化，并提示周围为软骨样基质（dense mineralization centrally with suggestion of chondroid matrix at the periphery）。MRI图像(b和c)显示C形软骨帽(最大8cm厚) [a C-shaped cap (maximum 8cm thick)]，其在T2WI呈高信号（high signal on T2-weighted images）。注意在轴位T2WI上病变的髓腔与宿主骨是相连续的(c)（the continuity between the medullary cavities of the lesion and the host bone）。鉴别诊断(前3位)骨软骨瘤 Osteochondroma软骨肉瘤 Chondrosarcoma骨表面骨肉瘤(骨旁) Surface osteosarcoma (parosteal)讨论此病变的鉴别关键点在于其是否与宿主骨相连续（whether t ………………………………