脊柱原始神经外胚层肿瘤的MRI表现

MRI appearance of primitive neuroectodermal tumor of spine

目的探讨原始神经外胚层肿瘤(PNET)的MRI特征,提高对该病的诊断水平。方法收集经手术病理证实的5例脊柱PNET患者,均行MRI增强扫描,分析其MRI特征,包括肿瘤部位、大小、形态、信号特点、强化方式、与脊髓关系、椎体骨质有无破坏等。结果肿瘤位于颈胸交界段椎管内1例、胸腰椎交界段1例,腰段椎管内1例,骶管内1例。肿块全部位于硬膜外,均经过椎间孔向椎(骶)管外生长形成椎旁软组织肿块影,3例肿块边界不清,2例肿块周围光滑,境界清楚,2例伴有溶骨性骨质破坏。T_1WI为低信号影,T_2WI为稍高信号影,2例肿块内出现小囊变区;增强扫描呈明显不均质强化。结论脊柱PNET多位于硬膜外,具有跨椎管内外生长,信号均匀或不均匀,明显不均质强化,易破坏椎体及附件结构,结合年龄较小,病史较短的患者应考虑脊柱PNET的可能,确诊依靠常规病理和免疫组织化学。

Objective To explore the MRI characteristics of primitive neuroectodermal tumor(PNET)and to improve the diagnosis of PNET.Methods 5 patients with spinal PNET proved by postoperative pathology were reviewed.All cases underwent contrast-enhanced MRI scans.The findings were analyzed which included the tumor location,size,morphology,signal characteristic,enhancement pattern,the relation between the lesions and spinal cord,the damage to centrum sclerotin.Results There were 1 intraspinal tumor at the cervicothoracic junction,1 case at the thoracolumbar junction,1 intraspinal tumor in the lumbar segment,and 1 sacral tumor.All were epidural lumps and grew out of the vertebral canal through intervertebrale foramen which formed the soft tissue masses near the vertebrae.3 tumors were poorly circumscribed,2 cases were well-demarcated with smooth surfaces,2 cases had osteolytic destruction.The cases showed low signal intensity on T 1WI and medium high intensity on T 2WI.2 cases had microcyst formation in the lumps.Enhanced scan showed inhomogeneous enhancement obviously.Conclusion The spinal PNET is often located in epidural area which grows cross the vertebral canal,shows homogeneous or heterogeneous signal,obvious inhomogeneous enhancement and usually destruct the centrum and the surrounding structure.The PNET should be taken into consideration when it comes to a younger patient with a short medical history.To confirm the diagnosis,pathological examination and immunohistochemistry are indispensable.