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目的探讨外周型原始神经外胚层肿瘤(peripheral primitive neuroectodermal tumors,p PNET)的CT与MR表现,以提高对本病的认识。方法回顾性分析12例经手术或穿刺活检病理证实的p PNET的CT及MR表现,其中3例行CT平扫、7例行CT平扫及增强检查,8例行MR平扫加增强检查。结果 4例位于髂骨、1例位于颈部、1例位于肩胛骨、2例位于胸壁、2例位于肋骨、1例位于腹膜后、1例位于盆底。5例软组织p PNET表现为巨大软组织肿块影,内见不同程度囊变、坏死。其中3例肿瘤边界不清,包绕、侵犯周围组织;2例边界清晰,周围组织受压、推移,未见侵犯征象;7例骨p PNET表现为溶骨性骨质破坏伴周围较大软组织肿块影,其中3例可见骨膜反应,2例呈短细垂直状,1例呈葱皮状;2例复发灶内见骨化影。肿瘤CT平扫呈软组织密度影,MR表现T1WI呈等、稍低信号影,T2WI呈稍高信号影,DWI呈高信号影,增强后呈不均匀强化。结论 p PNET临床及影像学表现缺乏特异性,CT、MR检查能清楚显示肿瘤边界、内部结构及相邻组织关系,有助于术前手术方案的确定和术后疗效的评价,确诊仍有赖于组织病理学和免疫组化检查。
Objective To investigate the CT and MR findings of peripheral primitive neuroectodermal tumors (p PNET) in order to improve the understanding of this disease. Methods We retrospectively analyzed the CT and MR findings of 12 cases of p-PNET confirmed by pathology or biopsy. Among them, 3 cases underwent CT scan, 7 cases underwent CT scan and contrast enhancement, and 8 cases underwent MR scan and contrast enhancement. Results Four cases were located in the ilium, one in the neck, one in the scapula, two in the chest wall, two in the ribs, one in the retroperitoneum and one in the pelvic floor. 5 cases of soft tissue p PNET showed massive soft tissue mass, see varying degrees of cystic degeneration, necrosis. Among them, the tumor border was unclear in 3 cases, and the surrounding tissues were infiltrated and encroached on. Surrounding tissues were infiltrated in 2 cases, and the surrounding tissues were compressed and pushed in without invasion signs. Seven cases of p PNET showed osteolytic osteolysis accompanied by surrounding soft tissues 3 cases showed periosteal reaction, 2 cases showed short vertical fine, 1 case was onion skin; 2 cases of recurrent lesions seen ossification. Tumor CT scan showed soft tissue density, MRI showed T1WI was equal, slightly lower signal, T2WI showed a slightly higher signal, DWI showed a high signal, enhanced uneven enhancement. Conclusion The clinical and imaging findings of p PNET are not specific. CT and MR examination can clearly show the relationship of tumor border, internal structure and adjacent tissues, which is helpful for the determination of preoperative surgical plan and evaluation of postoperative efficacy. The diagnosis is still dependent on Histopathology and immunohistochemistry.