Imaging findings for differentiating and predicting prognosis in undifferentiated pleomorphic sarcoma and myxofibrosarcoma.

OBJECTIVE

This study aimed to examine the imaging findings of undifferentiated pleomorphic sarcoma (UPS) and myxofibrosarcoma (MFS) and identify a prognostic factor for recurrence.

MATERIALS AND

METHODS

The research included 41 individuals who histopathologically and immunohistochemically confirmed UPS and MFS. MFS was histologically distinguished from UPS using the 10% myxoid area as the threshold value. MRI, CT, and 18F-fluorodeoxyglucose-PET/CT results were retrospectively examined and compared between the two diseases.

RESULTS

The results showed that 18 individuals had UPS, whereas 23 had MFS. The predominant signal intensity on T2-weighted images was low or intermediate in UPS (89 %) but high in MFS (87 %, p < 0.01). The tumor-to-muscle signal intensity ratio on T2-weighted images (2.8 vs. 3.8, p < 0.01) and apparent diffusion coefficient (ADC) values (0.93 vs. 1.52 × 10-3mm2/s, p < 0.01) were lower in UPS than in MFS. CT attenuation (37 vs. 22 Hounsfield Unit, p < 0.01) and maximum standardized uptake value (SUVmax) (15.6 vs. 5.2, p < 0.01) were greater in UPS than in MFS. Univariate analysis found that pathological diagnosis of UPS (hazard ratio: 15.6) and low or intermediate signal intensity on T2-weighted images (hazard ratio: 15.7) were predictors of recurrence.

CONCLUSION

The signal intensity on T2-weighted images, ADC value, CT attenuation, and SUVmax were relevant imaging results for distinguishing UPS from MFS. The pathological diagnosis and signal intensity on T2-weighted images were prognostic indicators of recurrence.