骨外尤文肉瘤/外周原始神经外胚层肿瘤的CT及MRI表现

CT and MRI imaging features of extraskeletal Ewing's sarcoma/peripheral primitive neuroectodermal tumor

目的:探讨骨外尤文肉瘤/外周原始神经外胚层肿瘤的CT及MRI表现及临床特点,旨在提高对该病的认识。方法:回顾性分析12例经病理证实的骨外尤文肉瘤/外周原始神经外胚层肿瘤的CT及MRI资料并复习相关文献,总结其影像学特征。结果:病灶位于鼻口咽3例,舌1例,颌下1例,鼻腔鼻窦3例,颈根部1例,胸腔2例,空肠1例。4例同时行CT及MRI平扫+增强检查,5例行CT平扫+增强检查,3例行MRI平扫+增强检查。病变为浸润性生长的软组织肿块,体积较大,密度或信号不均,增强后强化程度不一,3例DWI高b值扩散受限呈混杂高/稍高信号,对应ADC图为低信号。12例均伴坏死,2例伴钙化,12例均伴邻近结构受压移位,9例伴周围组织受侵,5例伴骨质破坏,5例病灶内部或边缘见血管影,2例MRI检查见流空血管影,3例伴淋巴结转移。结论:骨外尤文肉瘤/外周原始神经外胚层肿瘤的CT及MRI表现具有一定的特征:病灶多表现为体积较大的软组织肿块,占位效应明显,囊变坏死多见,钙化少见,易侵犯周围组织,病灶周围或内部常可见流空血管影。

Objective:To investigate the imaging manifestations and clinical features of extraskeletal Ewing's sarcoma(EES)/peripheral primitive neuroectodermal tumor and improve the recognition of it.Methods:The CT and MRI finding of 12 cases of EES proved by pathology were retrospectively analysed and related literatures were reviewed.The imaging features were summarized.Results:The lesions were located in oropharynx(n=3),tongue(n=1),mandible(n=1),nasal cavity and sinus(n=3),cervical root(n=1),thoracic cavity(n=2),and jejunum(n=1).Four cases underwent plain and enhanced CT and MRI scans,5 cases underwent plain and enhanced CT scans,3 cases underwent plain and enhanced MRI scans.Most of the lesions were characterized by large invasive soft tissue masses,with heterogeneous density or signal,and different enhancement patterns.Three cases showed diffusion restriction with slightly and remarkable hyperintense signal on DWI and hypointense signal on corresponding ADC maps.Among the 12 cases,all were accompanied with necrosis and mass effect,2 cases(16.7%)with calcification,9 cases(75%)with surrounding tissue invasion,5 cases(41.7%)with bone destruction,5 cases(41.7%)with intra-lesion or peripheral vessels,2 cases(16.7%)with flowing void vessels in MRI scans,and 3 cases(25%)with lymph node metastasis.Conclusion:There are some characteristics of CT and MRI findings in EES:lesions are usually large,which are often accompanied with necrosis,obvious mass effect,frequently invade or destruct the surrounding structures,high flow vascular around or in the lesion,lack of calcification.