中轴区原发外周型原始神经外胚层肿瘤CT和MRI表现

CT and MRI manifestations of the axial area primary peripheral primitive neuroectodermal tumors

目的 ：探讨中轴区原发外周型原始神经外胚层肿瘤（p PNETs）的CT和MRI表现,以提高对中轴区原发p PNETs的影像学认识。方法 ：回顾性分析2008年10月至2014年5月期间经病理证实的10例中轴区原发p PNETs患者临床资料,其中男7例,女3例;年龄8~49岁,中位年龄23.6岁。术前经多排螺旋CT平扫3例,平扫并增强4例;5例经MRI平扫并增强扫描;其中2例同时行CT及MRI检查。结果 ：骨内型6例,骨外型4例。发病部位及例数分别为骶椎3例,腰椎2例,颈椎1例,颈椎椎管1例,尾骨1例,右髂骨1例,骶前间隙1例。横断位最小肿瘤最大层面大小1.1 cm×1.2 cm,最大者8.0 cm×9.2 cm,中位大小4.4 cm×5.7 cm,其中6例最大径线＆gt;5 cm。其中溶骨性破坏5例,2例伴钙化,混合性1例,2例无骨质破坏。CT以等密度为主,1例密度均匀,余6例密度不均,其中3例可见＂浮冰＂样改变,增强扫描1例中度强化,余3例明显强化,2例内见多发小血管。MRI在T1WI上5例均为等信号,在T2WI上均为稍高信号,信号不均,增强后5例均强化明显。2例伴椎体压缩性骨折,10例均未见骨膜反应,5例MRI检查无椎间盘破坏。结论：中轴区原发p PNETs以儿童及青年多见,肿块常较大。骨内型肿块常包绕椎体,并以椎前间隙为主,均伴椎体骨质破坏,溶骨性常见,椎体原发多见,附件原发或受累少见,可累及椎管,以前壁受累常见,可伴多发新生小血管;骨外型以深部软组织间隙常见,少数原发于椎管,多伴椎体骨质破坏,以溶骨性为主。不侵及椎间盘,椎间隙不窄。CT可伴＂浮冰＂征,以骨内型常见。MRI T1WI以等信号为主,T2WI以稍长信号为主,增强强化明显。

Objective：To explore CT and MRI manifestations of the axial area peripheral primitive neuroectodermal tumors（p PNETs） in order to improve the knowledge of this disease. Methods：The clinical data of 10 patients with p PNETs underwent pathologically confirmed were retrospectively analyzed from October 2008 to May 2014. There were 7 males and 3 females,aged from 8 to 49 years old with median of 23.6 years. The preoperative multi slice spiral CT scan was completed in 3cases,plain CT scan and enhancement in 4 cases;MRI and enhancement scanning in 5 cases;and among them,2 cases underwent both MRI and CT scan. Results：In bone type was found 6 cases and out bone type was found 4 cases. Three cases occurred in sacral vertebrae,2 cases in lumbar vertebrae,1 case in cervical vertebrae,1 case in cervical spinal canal,1 case in coccyx,1 case in the right iliac bone,1 case in presacral space. Cross sectional the smallest tumor maximum level was 1.1 cm×1.2 cm in size,the biggest tumor was 8.0 cm×9.2 cm,the median size was 4.4 cm×5.7 cm,of them,the tumor of maximal diameter larger than 5 cm had 6 cases. Except 2 cases without destruction of bone,the other 5 cases with osteolytic destruction,2cases with calcification,1 case with mixed. Equidensite was main in CT scan,1 case with uniform density,other 6 cases with uneven density,in which 3 cases with ＂floating ice＂ change;1 case with moderate strengthening,other 3 cases with obviously strengthening,2 cases with multiple small blood vessels in enhancement scanning. MRI of 5 cases showed the signal of isointensity on T1 WI,the slightly high signal on T2 WI and the signal was not uniform;after enhancement scan,the signal of 5 cases obviously enhanced. Two patients complicated with vertebral compression fractures,no periosteal reaction was found in all patients,and no the destruction of intervertebral disk was found in 5 patients of MRI scan. Conclusion：The axial area p PNETs is common among children and the youth,and the mass often is huge. The mass of in bone type often envelopes the vertebral body,and main located on prevertebral space,all associated with bone destruction,osteolytic destruction is common,and primary vertebral bodies also is common,attachment primary or involvement is few found,it can involve the spinal canal and anterior wall of spinal canal is common,some cases complicate with multiple newly born small vessels. The mass of out-bone type in deep soft tissue is common,minority primary spinal canal,many complicated with vertebral bone destruction,osteolytic destruction was main. The intervertebral disk was not invaded and intervertebral space has not stenosis. CT scan offer complicate with ＂floating ice ＂ sign,and in-bone type is common. Isointensity is main on MRI T1 WI and slightly longer signal is main on MRI T2 WI,strengthening signal is obvious.