MRI manifestations of primary primitive neuroectodermal tumors/Ewing sarcoma in the intraspinal canal of children

SU Xiaoran; SHI Shengli; JING Changyou; CHEN Wan; ZHENG Bin; LIU Yue

doi:10.19300/j.2025.L21526

Abstract：Objective To analyze the MRI imaging characteristics of primary primitive neuroectodermal tumors/Ewing sarcoma(PNET/ES)in the intraspinal canal of children.Method A retrospective analysis was conducted on the MRI imaging findings of six children with pathologically confirmed primary spinal epidural PNET/ES.Results All six cases of PNET/ES were single lesions located in the thoracic spinal canal.In five cases,the lesions were in the spinal epidural space,extending toward the adjacent intervertebral foramina and presenting a dumbbell shape.Four cases involved adjacent vertebrae or paravertebral tissues,and one tumor was located in the subdural space.All tumors had clear boundaries,with the largest measuring 39 mm×26 mm×45 mm and the smallest measuring 11 mm×5 mm×15 mm.Four tumors were predominantly solid,showing isointensity on both T1WI and T2WI sequences,isointense/slightly high signal on fat-saturated T2WI,diffusion restriction,and significant enhancement on contrast-enhanced MRI.In two cases,necrosis occurred within the tumors:one tumor exhibited cystic necrosis with low signal on T1WI,high signal on T2WI,and high signal on fat-saturated T2WI;the other had coagulative necrosis combined with surrounding soft tissue infection,showing slightly low signal on T2WI and fat-saturated T2WI,with ring enhancement on contrast-enhanced MRI.Among the six cases,one had complications of Trousseau's syndrome with extensive metastasis to the brain parenchyma,meninges,and spinal meninges,presenting as right hemisphere cerebral infarction changes and widespread nodular and linear metastatic lesions in the brain parenchyma,brain cisterns,and leptomeninges.Conclusion The MRI manifestations of primary spinal epidural PNET/ES in children have certain characteristics and may be associated with Trousseau's syndrome and multiple metastases,which require special attention in clinical practice.