椎旁原始神经外胚层瘤CT和MRI诊断

Primitive Neuroectodermal Tumor of Paravertebral Region:CT and MRI Diagnosis

目的:研究椎旁外周性原始神经外胚层瘤(pPNET)的CT及MR表现,提高对该病的认识。方法:报道5例经手术病理证实的pPNET的临床、CT、MRI及组织学所见,并复习相关文献。结果:5例均见单侧椎旁肿块,累及椎管内硬膜外,肋骨骨质侵蚀,胸髓受压变形;CT显示肿块形态不规则、密度均匀;MRI示T1WI肿块信号均匀、略高于邻近骨骼肌信号,T2WI呈不均匀高信号,增强后肿块明显均匀强化。术后MRI显示局部肿块复发和胸腔积液,CT发现肺部、纵隔多发转移结节。结论:pPNET为少见的起源于胸壁、椎旁的恶性肿瘤,其CT、MRI表现无特征性,但可明确肿瘤的范围、进行手术切除可能性评估及治疗后随访。CT易显示肋骨、椎体骨质破坏、肺部小转移灶,MRI则可显示胸壁受累、胸髓受压变形的程度和范围等。

Objective：To study the CT and MRI appearances of peripheral primitive neuroectoderal tumor （pPNET） of paravertebral region. Methods： Clinical, CT, MRI and histological findings in 5 patients with pathologically proved pPNETs were studied and literature about pPNET was reviewed. Results：Unilateral paravertebral masses invading epidural space of spinal canal,with ribs erosion and thoracic spinal cord displacement and deformation were seen in all 5 patients. On CT scans,all tumors were irregular in shape and homogeneous in attenuation. Tumors were homogenous with signal intensity greater than that of skeletal muscles （on MRI T1 WI）,and heterogeneous high signal intensity on T2 WI. Marked homogeneous enhancement can be revealed on T1 WI after contrast administration. Follow-up imaging examination after surgery, local recurrence and pleural effusions can be easily noted on MRI as well as lung,mediastinal lymph node metastases detected on CT. Conclusion： No specific CT and MRI findings can be found in this rare malignant neoplasm originating in soft tissues of the paravertebral region, but CT and MRI are useful in delineating the extent of tumor,predicting the resectability, as well as in monitoring treatment response. CT scanning is preferred for detecting skeletal destruction and small pulmonary metastases. MRI is superior in providing information of chest wall muscles invasion and the degree and extent of spinal cord involvement.