目的分析长骨皮质旁骨肉瘤的 临床及影像表现特征，以提高对该病诊断 和鉴别诊断的能力。方法 分析研究12例 经手术病理证实的长骨皮质旁骨肉瘤的临 床及影像学资料, 其中发生在股骨近端2 例，股骨远端8例，肱骨近端及胫骨近端 各1例。结果 长骨皮质旁骨肉瘤X表现为 紧贴骨皮质的分叶状外生肿块, 4例显示 肿块与骨皮质间透亮线。CT表现为软组织 肿块内见团状及菜花状不规则高密度瘤骨 影。在MRI上，肿瘤T1WI加权呈低信号， T2WI加权呈高信号为主的混杂信号，T1WI 增强扫描肿瘤的实性成分可见强化。CT、 MRI均可显示肿瘤的软组织成分及对髓腔 的侵犯，本组有4例髓腔受累，其中1例CT 未显示。结论 皮质旁骨肉瘤的影像学表 现具有特征性，CT、MRI可清晰地显示肿 瘤及其周围组织，对指导临床诊断与治疗 具有重要的参考作用。

Objective To investigate the imaging features of long bone parotsteal osteosarcoma. Methods The clinical data and images of 12 patients with long bone parotsteal osteosarcoma confirmed operatively were reviewed. 2 cases occurred in proximal femur, 8 cases occurred in distal femur，and 1 case occurred in proximal humerus and tibia. Results 12 cases of long bone parosteal osteosarcoma showed lobulated and exophytic mass attached to the underlying cortex on X-ray. A radiolucent line between the tumor and the normal cortex was noticed in 4 cases. CT scan demonstrated soft tissue mass with focal or cauliflower-like high density tumor bone in it. The lesions appeared as low signal intensity on T1WI and mixed mainly high signal intensity on T2WI. The signal density of the solid component in tumor was increased after gadolinium was injected. Both CT and MRI showed solid component in tumor and the marrow involvement. The marrow was involved in 4 cases, one was missed in CT finding. Conclusion There were characteristic imaging manifestations of the neoplasm. CT and MRI can clearly show the neoplasm and its surrounding tissues, and it's an improtant reference in the diagnosis and surgical treatment .