ABSTRACT
Objective To explore the MR findings of extra?abdominal desmoid?type fibromatosis and the related features of recurrence. Methods MRI and clinical data of 36 cases of extra?abdominal desmoid?type fibromatosis proved by surgical pathology were retrospectively reviewed between March 2010 and October 2016.The ages of the cases ranged from 10 years to 68 years. 14 males and 22 females were included with sex ratio 1∶1.57.the courses of the disease were varied from 1 day to 8 years. The stage was based on Church′s method. 3 cases were only with plain scan and other 33 cases with contrast enhancement. Sagittal or coronal T1WI, STIR?T2WI, PdWI and contrast enhanced T1WI in horizontal, sagittal and coronal view were examined on MR siganl 1.5T or 3.0T of GE Company. Two groups were divided based on the recurrence or not after surgery. The clinical and MR features were analyzed between the two groups with χ2 test, t test or Spearman rank correlation analysis according to the data characteristics. Results Compared with signal intensity of muscle, 34 cases were isointense and 2 cases isointense with hypointense area on T1WI; 34 cases were hyperintense and 2 cases hyperintense with hypointense area on T2WI. On contrast enhanced imaging, 22 cases were markedly enhanced, 7 cases moderately enhanced and 4 cases mildly enhanced.15 cases was with recurrence and 21 cases without recurrence. Infiltration of surrounding tissue was shown in 14 cases(38.9%), 13 cases with recurrence and 1 cases without recurrence. Band sign was shown in all cases. Tentacle sign was shown in 18 cases (50.0%), 15 cases with recurrence and 3 cases without recurrence. Split fat sign was shown in 12 cases (33.3%) and all without recurrence. Fascial tail sign was shown in 15 cases (41.7%), 13 cases with recurrence and 2 cases without recurrence. Hypointense ring around the tumor was shown in 21 cases (58.3%), 2 cases with recurrence and 19 cases without recurrence. The P value of tentacle sign, split fat sign, hypointense ring around the tumor, fascial tail sign and infiltration of surrounding tissue was less than 0.05. Gender, location and the degree of contrast enhancement was without difference of statistical significance between the two groups. There was significant correlation of the recurrence rate with the courses and the stage of the disease(χ2=7.264 , r=0.994 , P<0.05). Conclusions Tentacle sign, fascial tail sign and infiltration of surrounding tissue were attributed to the estimate of recurrence of extra?abdominal desmoid?type fibromatosis, and Be features contributes to the diagnosis and therapy of extra?abdominal desmoid?type fibromatosis.