CT and MRI Findings of Primary Low-Grade Malignant Myofibroblastic Sarcomas of Soft Tissue

Objective To discuss CT and MRI features of primary low-grade malignant myofibroblastic sarcomas of soft tissue in order to improve its diagnostic level.Methods A total of 9 patients with pathologically-confirmed primary lowgrade malignant myofibroblastic sarcoma of soft tissue were enrolled in this study.Simple CT scanning was performed in 4cases,simple MRI was employed in 4 cases,and both CT and MRI were carried out in one case.The imaging manifestations were retrospectively analyzed.Results Among the 9 cases with primary low-grade malignant myofibroblastic sarcoma of soft tissue,the lesion had a clear border on CT scan in 2,showed a large number of irregular calcification in 2.Contrastenhanced CT scanning was employed in 4 cases,and in arterial phase obvious heterogeneous enhancement was demonstrated in 2 cases,moderate enhancement at the tumor periphery was seen in 2 cases.Venous phase scanning was performed in only one patient,which showed that the enhancement degree of the tumor became further increased.Bilateral pulmonary metastasis was detected in one case.On MRI the lesion was characterized by long T1 and long T2 signals.In 3 cases the lesions displayed obvious enhancement on contrast-enhanced scanning and in 2 cases significant peripheral enhancement was observed.The liquefaction or necrosis area within the tumor showed no enhancement.Conclusion Primary low-grade malignant myofibroblastic sarcomas of soft tissue are lack of characteristics CT and MRI signs,the confirmation of the diagnosis depends on the pathology examination.