MRI and pathological findings of low-grade fibromyxoid sarcoma / 中华放射学杂志

ABSTRACT

Objective To investigate the MRI characteristics of low grade fibromyxoid sarcoma (LGFMS).Methods The MRI imaging of 13 cases with operation and pathology proven low grade fibromyxoid sarcoma were retrospectively analyzed.Comparative study of the relationship between the signal,boundary,cystic,and the enhancement degree with tumor tissue components was performed.Results The tumors were located in thigh (n=7),lower leg (n=3),elbow,shoulder and upper arm (n=l for each).The average diameter of tumor was (7.01 ±2.89) cm (range from 2.5 to 12.0 cm).The tumors with maximal diameter larger than 5 cm were seen in 11 patients.All tumors had well-defined margin.Necrosis and cystic change was seen in 5 tumors,tumor compartment in 3 cases,intratumoral fluid fluid level in 2 cases,and peritumoral edema in 3 cases.T1WI showed hypointensity in 6 cases,iso-,hopointensity in 4 cases,isointensity with slightly hyperintensity in tumor center in 4 cases,heterogeneous intensity in 1 case.T2WI showed hyperintensity in 6 cases,central higher intensity in 4 cases,hyper-,iso-,hypo-intensity in 4 cases,and hyper-,hypo-intensity in 3 cases.T2WI with fat suppression sequence showed hyper-,iso-,hypo-intensity in 8 cases and high intensity solid part and much higher intensity in tumor center in 5 cases.Heterogeneous enhancement of the tumors was noted,including mild enhancement in 8 cases,moderate enhancement in 4 cases,and marked enhancement in one case.Pathological results showed that the tumors were gray and white or yellow,well-defined,and hard texture,in which 5 cases cystic degeneration with tremelloid material can be seen in 5 cases.Microscopy results showed alternating distribution of fibrous and myxoid areas.Nine cases had rosettes formation and characteristic arcuate vessels were seen in 2 tumors.Immunohistochemical results showed negative Vimentin,Desmin,and S-100 in 5 patients,while 3 patients were positive for SMA and CD34.Conclusions LGFMS has some characteristic MRI finding.Combination of MRI and the clinical findings can suggest the diagnosis of LGFMS,however,the final diagnosis depends on pathological examination.