CT and MRI findings of Ewing's sarcoma/primitive neuroectodermal tumor of the kidney

YE Yu; ZHOU Xin

doi:10.20258/j.cnki.1006-9011.2025.12.016

Abstract：Objective To investigate the CT and MRI features of Ewing's sarcoma/primary neuroectodermal tumor(ES/PNET)of kidney.Methods The clinical data and imaging findings of 5 patients with kidney ES/PNET confirmed by operation and pathology were retrospectively analyzed,and their CT and MRI manifestations were analyzed combined with the literature.Results Among the 5 cases of kidney ES/PNET,there were 4 females and 1 male,with age ranged from 28 to 51 years.The me-dian age was 33 years.The tumors were all large solitary masses(4 cases in the left kidney and 1case in the right kidney)with a maximum diameter from 9.0 to 18.5 cm.Plain CT revealed soft tissue mass shadows with uneven density.Among these,four cases showed internal septas and cystic areas within the lesions,with mild enhancement of the solid components and septas on contrast-enhanced scans.One case exhibited no significant cystic areas within the lesion,demonstrating mild homogeneous en-hancement on contrast-enhanced scans.On MRI non-contrast scans,all five lesions showed iso-or slightly hypointense signals on T1WI and heterogeneous signals on T2WI.Diffusion-weighted imaging(DWI)revealed restricted diffusion in the solid compo-nents of the masses.Contrast-enhanced MRI demonstrated mild enhancement in the solid portions and septas of the lesions.All tumors were associated with ipsilateral renal vein and inferior vena cava tumor thrombus.Conclusion Renal ES/PNET is a rare neoplasm occurring in young adults.It presents as a unilateral large endophytic infiltrating mass,often accompanied by multiple irregular septas,rare calcification,and inhomogeneous mild enhancement.And it is highly prone to develop with the combina-tion of ipsilateral renal vein and inferior vena cava tumor thrombosis.