外周原始神经外胚层肿瘤的 CT及MRI 表现

目的：探讨外周原始神经外胚层肿瘤（pPNET ）的CT 及MRI表现。方法回顾性分析9例经病理证实的pPNET 的CT、MRI表现及病理特点。其中8例行CT平扫和（或）增强扫描；5例行MRI平扫和（或）增强扫描。结果病灶位于头颈部2例，胸部3例，阴囊1例，右肩胛区1例，下肢2例。病灶7例为单发，呈类圆形或不规则形，分叶状，最长径约为1．6～13．8cm，平均6．2cm。8例与周围组织分界不清。CT平扫呈以等密度为主的混杂密度；MRI平扫 T1WI为等稍低信号，T2WI多为不均匀高信号。增强扫描呈多种强化表现，常见为中度以上不均匀强化。其中3例与邻近骨关系密切，表现为溶骨性骨质破坏。结论 pPNET CT及M RI表现缺乏特征性，对临床的定位及定性诊断有一定的帮助。

CT and MRI appearances of peripheral primitive neuroectodermal tumors

Objective To explore CT and MRI features of peripheral primitive neuroectodermal tumors (pPNET) .Methods CT and MRI findings were retrospectively analyzed in 9 cases with pPNET confirmed by pathology .Of them ,8 patients underwent CT imaging ,and 5 patients underwent MR imaging .Results The lesions occurred in head and neck in 2 cases ,chest in 3 cases ,scrotum in 1 case ,right scapular region in 1 case ,and lower extremity in 2 cases .The lesions were more solitary (7/9) with round ,lobular or irregular shape .The longest diameter was between 1 .6 cm -13 .8 cm ,and the median diameter was 6 .2 cm .8 cases had blurred boundary .On CT plain scanning ,the lesions were mixed density with predominant isodensity .On MR imaging ,the lesions were slightly T1 hypointensity and heterogeneous T2 hyperintensity .Enhancement patterns were varied ,and the common way was mild‐to‐moderate heterogeneous enhancement .3 cases of them were closely associated with bone ,and showed osteolytic bone destruction . Conclusion The CT and MRI features of pPNET has lack characteristics ,CT and MR imaging have some value for localization diagnosis .