RESUMEN

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.