外周性原始神经外胚层肿瘤的影像学表现

Imaging features of peripheral primitive neuroectodermal tumors

目的探讨外周性原始神经外胚层肿瘤（pPNETs）的X线、cT及MR／表现。方法回顾性分析14例经病理证实的pPNETs患者的X线平片、螺旋CT及MRI表现，其中12例子X线平片检查，11例子cT检查，5例予MRI检查。结果发生在软组织的pPNETs共8例，X线及cT表现为分界不清的等或低密度软组织肿块，部分肿瘤破坏相邻骨质；MRI表现为软组织内边界不清的较大肿块，其内信号不均匀，相邻骨皮质及部分骨髓腔为软组织影替代；肿块均有不同程度的不均匀强化。发生在骨的pPNETs6例，X线及CT表现为范围较大的溶骨性骨质破坏，破坏骨的周围伴有大小不等的软组织肿块；病灶在T1WI表现为等或低信号，T2WI为中等或高信号肿块，不均匀中度或明显强化。结论pPNETs具有一定的影像学特点，X线平片、CT与MRI检查有助于术前了解病变的性质、范围、分期等，具有重要的临床应用价值。

Objective To investigate the X-ray, CT and MRI features of peripheral primitive neuroectodermal tumors （pPNETs）. Methods 14 patients were pathologically diagnosed with pPNETs. The imaging of X-ray （twelve image）,Computed Tomography（eleven image） and Magnetic Resonance Imaging（ five image） were retrospectively analyzed. Results Of 14 patients, there were two sites of tumour： soft tissue （ eight patients） and hones （ six patients ）. For tumours of the soft tissue region, the appearance of X-ray and CT imaging showed equal or lower density soft mass without clear boundary. In some cases, tumours invaded adjacent bones. The appearance of MRI imaging showed large heterogeneous masses inside soft tissue without clear boundary. Tumours displaced adjacent cortical bone and eavitas meduUaris. All masses were heterogeneous enhancement on contrast images. For tumours of bone region, X-ray and CT scan showed large scale osteolysis osteoclasia in bone surrounding with soft tissue masses of various size. The lesions were equal or lower signal on T1 WI. All masses were intermediate or hyperintense signal with hetero- geneous midrange or obvious enhancement on T2 WI. Conclusion Imaging characteristics of pPNETs were described. X-ray,CT and MRI were useful in understanding the property,extent and staging of tumor and very useful in the diagnosis.