外周型原始神经外胚层肿瘤的影像学表现

Imaging Manifestations of Peripheral Primitive Neuroectodermal Tumor

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 neuroectodennal 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 enhaucement, immature blood vessels were seen in some lesions. Conclusion hnaging 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.