多层菊形样胚胎性肿瘤影像学表现

Imaging findings of embryonal tumor with multilayered rosettes

目的观察多层菊形样胚胎性肿瘤(ETMR)影像学表现。方法回顾性分析8例经病理证实ETMR患儿的MRI(n=8)和CT(n=6)资料,观察其影像学表现。结果MRI中,8例ETMR最大径32~96 mm,边缘清晰,5例位于幕上、3例位于幕下;幕上ETMR均为巨大囊实性肿块,幕下ETMR体积较小,均未见瘤周水肿。6例ETMR为囊实性,囊性部分呈低T1WI、高T2WI信号且均位于肿瘤边缘,增强后5例实性部分轻度局灶性不均匀强化、1例未见明显强化;其中5例见瘤内出血,5例瘤内见流空血管影,3例侵犯邻近硬脑膜。2例ETMR为实性,增强扫描可见局灶性结节状不均匀强化,且强化部分与表观弥散系数(ADC)图上的低信号区对应;其中1例胆碱(Cho)/肌酸(Cr)升高,N-乙酰天冬氨酸(NAA)降低。弥散加权成像(DWI)中,8例ETMR均显示弥散受限。6例接受CT扫描的患儿中,4例见条片状或点状钙化,与MRI低信号区对应。结论ETMR多为幕上较大囊实性肿块,边缘清楚,囊变常位于肿瘤边缘,可见特征性血管流空影,常伴瘤内出血,可见钙化,无瘤周水肿,DWI明显弥散受限;增强后实性部分轻度不均匀强化。

Objective To observe the imaging findings of embryonal tumor with multilayered rosettes(ETMR).Methods MRI(n=8)and CT(n=6)data of 8 children with pathologically confirmed ETMR were retrospectively reviewed,and the imaging findings were analyzed.Results ETMR present as masses with the maximum diameter of 32—96 mm and clear edges in all 8 cases,located supratentorially in 5 and infratentorially in 3 cases.The supratentorial ETMR were giant cystic solid masses,while the infratentorial ETMR had relatively small volumes.No peritumoral edema was noticed.Cystic solid masses were observed in 6 cases,and the cystic portion presented as low T1WI and high T2WI signals at the edge of the masses.After administration of contrast agents,mild focal uneven enhancement in the solid portion was found in 5 cases,while 1 case was not found enhancement.Among the above 6 cases,the intratumoral bleeding and empty blood vessel shadows within the masses were observed each in 5 cases,while adjacent dura mater invasion was noticed in 3 cases.Two ETMR present as solid masses with focal nodular uneven enhancement,and the enhanced area corresponded to the low signal area on apparent diffusion coefficient(ADC)image,among them,increased choline(Cho)/creatine(Cr)and decreased N-acetyl aspartate(NAA)was found in 1 case.Limited diffusion on diffusion weighted imaging(DWI)were detected in all 8 cases.Among 6 cases who underwent CT scanning,patchy or punctate calcification,corresponding to the low signal area on MRI were detected in 4 cases.Conclusion ETMR mostly present as supratentorial large solid cystic masses with clear edges,and the cystic portion often located at the edge of masses,with characteristic vascular flow voids often accompanied by intratumoral bleeding and some with calcifications but without peritumoral edema,which showed significantly limited diffusion on DWI and weakly inhomogeneous enhancement of the solid part.