目的 探讨骨盆尤文氏肉瘤/外周型原始神经外胚层肿瘤（ES/pPNET）的影像学表现，并与临床及病理对照，进一步 加深对该病的认识。方法 回顾性分析经病理证实的8例骨盆原发性ES/pPNET临床、病理及影像学资料。所有病例均 行常规X检查，其中4例同时行CT检查，7例行MR检查。影像学观察指标包括：发病部位、数目、骨质破坏、骨膜反 应及瘤骨、软组织肿块、强化方式等。病理学观察指标包括形态学和免疫组织化学。结果 7例表现为溶骨性骨质破 坏；1例表现以骨硬化为主要改变；7例见与骨质破坏不呈比例的巨大的软组织肿物，中央区多发坏死囊变；最大径 大于8cm的肿瘤6例；4例跨关节浸润。MRI显示软组织肿物内可见T2WI低信号分隔影，增强扫描部分强化。6例出现 转移，其中3例为肺转移。免疫组化8例患者CD99均为阳性表达。结论 原发于骨盆的ES/PNET具有一定特点，但缺乏 特异性，确诊仍需组织病理学检查。对于青少年患者，结合影像学上溶骨性骨质破坏并明显软组织肿块，需考虑骨 盆ES/PNET可能。

Objective To discuss the imaging findings of ES/pPENT in pelvic bones and to improve the cognition. Methods Eight patients with ES/pPENT in pelvic bones with pathologically proved were retrospectively analyzed for their clinical, pathologic and radiologic features. All the patients were underwent X-ray examination, 4 patients performed CT examination, and 7 patients performed MR. Imaging findings include: the location, number, bone destruction, periosteum reaction and bone, soft tissue mass, and enhancement mode. Pathological examination of the observed indicators include morphology and immunohistochemistry. Results 7 cases showed osteolytic bone destruction; and only one case showed sclerosis bone destruction .7 cases showed huge and uneven density soft tissue mass with bone destruction, and in 6 cases which the maximum diameter of the tumor were more than 8cm.4 cases involved the adjacent joints; MR imaging showed line dark signal interval in soft tissue mass on T2WI, with partly enhancement. 6 cases was found with metastases, and 3 were in pulmonary. Immunohistochemical CD99 of all cases were positive expression. Conclusion ES/pPENT shows certain characteristics, but lacks the specificity. Pathological examination is mandatory to confirm the diagnosis. For young patients with bone destruction and soft tissue mass, the chance of ES/ pPNET should be considered.