An analysis of factors related to the tail-like pattern of myxofibrosarcoma seen on MRI

Myxofibrosarcoma (MFS) is characterized by a high frequency of local recurrence after surgery because of infiltrative growth of the tumor cells. This infiltrative growth creates a characteristic ‘tail-like’ pattern on magnetic resonance imaging (MRI), and it has been reported that this pattern is especially obvious on gadolinium-enhanced MRI (Gd MRI). However, the relationship between the tail-like pattern seen on Gd MRI and clinicopathological features of MFS is still not clear. In this study, we performed a retrospective analysis to identify clinicopathological factors related to the tail-like pattern of the MRI findings in patients with MFS. We retrospectively analyzed 50 patients with MFS to identify factors related to the tail-like pattern. On Gd MRI, 32 of the 50 patients presented the tail-like pattern, whereas 18 presented a solid pattern. The clincopathological factors related to the tail-like pattern were evaluated by chi-squared test. A superficial origin (p = 0.0009) was most significantly related to the tail-like pattern. The 5-year recurrence-free survival (RFS) rate was 75.6 % for patients showing the tail-like pattern and 90.9 % for those showing the solid pattern. The corresponding 5-year disease-free survival (DFS) rates were 64.7 and 79.3 %, respectively. Thus in terms of both 5-year RFS and DFS, patients with the tail-like pattern tended to have a poorer outcome. A superficial origin of MFS is significantly related to a tail-like pattern on Gd MRI. The tail-like pattern is associated with poorer prognosis. Further studies of tumor depth and the tail-like pattern on Gd MRI are needed.