目 的 探讨外周型原始神经 外胚层肿瘤(peripheral primitive neuroectodermal tumor，pPNET)的影像 表现，以期提高对其认识。方法 收集我 院2011年1月-2015年12月经穿刺及手术 病理证实的pPNET10例，分析其影像学表 现。4例行CT平扫和增强扫描，2例行PETCT检查，4例行MRI平扫和增强扫描。结 果 1例发生于鼻腔，2例发生于骨骼，8例 发生于软组织，肿块密度及信号欠均匀， 其内可见囊变坏死区，但未见钙化。CT表 现为不均质软组织密度，MRI信号混杂， T2WI、DWI、T2脂肪抑制以高信号为主， T1WI以高信号为主，所有病灶周围均未见 肿大淋巴结。其中发生于鼻腔及腹盆腔者 表现为分叶样软组织肿块，呈浸润性生 长，压迫被侵犯临近组织。发生于胸壁及 骨骼者，破坏临近骨质，破坏区未见硬化 边、骨膜反应及瘤骨形成。2例行PET-CT 检查者，见异常放射性浓，最大标准化摄 取值(suvmax)分别为5.4、11.7。增强扫 描后除1例发生于胸壁者轻度强化，其余 病灶表现为明显不均匀强化，部分病灶内 可见不成熟血管影。结论 pPNET的影像表 现缺乏特异性，但能较好显示肿瘤的内部 结构，明确肿瘤的范围和发现远处转移。

Objective To explore imaging findings of peripheral primitive neuroectodermal tumor (pPNET), in order to improve the understanding of it. Methods Collect confirmed pPNET 10 cases by biopsy and surgical pathology from January, 2011 to December, 2015 in our hospital, and analyze its imaging findings. 4 cases of them underwent CT plain scanning and enhanced scanning, 2 cases underwent PET-CT examination, 4 cases underwent MRI plain scanning and enhanced scanning. Results 1 case occurred in nasal cavity, 2 cases occurred in bone, 8 cases occurred in soft tissue, and the mass density and signal are less homogeneous, cystic necrotic area inside can be seen, but with no calcification. CT shew that soft tissue density was not homogeneous, MRI signal was mixed, T2WI, DWI, T2 fat suppression was centered to high signal, T1WI was centered to high signal, no swollen lymph nodes were found all around the lesions. Those of which occurred in nasal cavity and abdominal pelvic manifested themselves as leaf - like soft tissue masses, they developed with invasive growth, and oppressed violated adjacent tissues. Those of which occurred in the chest wall and bones destroyed adjacent bone, sclerotic margins, periosteal reaction and the formation of tumor bone were not found in damaged area, 2 patients undergone PET-CT examination were found having abnormal radioactive concentrations, SUVMAX was respectively 5.4, 11.7. After enhanced scanning, except that 1 case occurred in chest wall had mild enhancement, the rest of the lesions shew obviously heterogeneous enhancement, immature blood vessels were seen in some lesions. Conclusion Imaging findings of pPNET lacks specificity, but it can better show the internal structure of the tumor, make clear of the scope of tumor and find if it metastases to distant parts.