外周性原始神经外胚层肿瘤的影像学表现与病理对照分析

目的 探讨外周性原始神经外胚层肿瘤（pPNET）的影像学表现,以提高对本病的认识和诊断的准确性.方法 回顾性分析经病理证实的9例pPNET患者的临床及影像学资料.患者年龄11～67岁,男7例,女2例.9例全部行CT平扫加增强扫描,其中4例行MR平扫加增强扫描,3例行X线平片检杳.结果 9例病灶中1例位于鼻腔,3例位于胸壁,3例位于腹腔,1例位于子宫,1例位于锁骨.8例软组织pPNET CT表现为多数较大且呈浸润性生长的软组织肿块,伴或不伴邻近骨质的溶骨性破坏,肿块内密度不均匀伴坏死囊变,不伴钙化,增强后呈中等程度以上不均匀强化.1例骨pPNET表现为较大的溶骨性骨质破坏伴软组织肿块,增强后病灶明显不均匀强化.MRI示病灶T1WI呈等信号1例,等、低混杂信号2例,中等稍高信号1例;T2WI均呈不规则中、高信号,部分病例可见假包膜或分隔样改变;4例钆喷酸葡胺（Gd-DTPA）增强后均表现为不均匀强化.病理形态上Homer-Wright 菊彤团为其特异性表现,免疫组织化学显示肿瘤均表达CD99和NSE,并不同程度表达波形蛋向（Vim）、上皮细胞膜抗原（EMA）、突触素（Syn）、胶质纤维酸性蛋白（GFAP）等,但不表达白细胞共同抗原（LCA）等.结论 CT、MRI能较好地显示肿瘤的内部结构、明确肿瘤的范围,具有较大的诊断价值.

Imaging findings and pathological analysis of peripheral primitive neuroectodermal tumors

Objective To study the imaging features of peripheral primitive neuroectodermal tumors （pPNETs） in correlation with pathological findings. Methods The clinical information and imaging of 9 patients with pathologically proven pPNETs were reviewed. Imaging examinations included radiographs （3）, CT （9） and MRI （4）. Results The 9 tumors were located in the nasal cavity （1）, chest wall （3）, peritoneal cavity （3）, uterus （1）, and clavicle （1）. CT showed large, ill-defined, non-calcified heterogeneous soft tissue masses with cystic areas and heterogeneous contrast enhancement. The bone lesions were lytic associated with large soft tissue masses and heterogeneous contrast enhancement. MRI showed isointensity （1）, iso- to hypointensity （2）, iso- to hyperintensity （1） on T1WI. In T2WI, The tumors were iso- to hyperintense on T2WI. Four lesions enhanced heterogeneously with gadolinium. Some lesions showed false capsule and septation. Homer-Wright daisy-group was a specific pathologic feature of pPNETs. Immunohistochemical analysis showed CD99 and NSE positivity and LCA negativity in all lesions. Conclusion CT and MRI can demonstrate the internal structures and extent of the pPNETs, which are beneficial for diagnosis.