FIGURE 4.

A 47-year-old woman with desmoid-type fibromatosis in the right axilla with progression (Group 1). This was misdiagnosed as a sarcoma on preoperative CT but as fibromatosis on preoperative MR. The tumor shows iso-signal intensity on coronal T1-weighted image (A) and high signal intensity on axial T2-weighted image (B). The margin is partially ill-defined (white arrows) on axial T2-weighted image (B). A rim of surrounding fat (white arrows) with high signal intensity is clearly seen on T1-weighted image (A). On enhanced T1-weighted axial (C) and coronal (D) images, the tumor shows strong and heterogeneous enhancement with a central area of nonenhancing low signal bands (black arrows). The maximal standardized uptake value on FDG PET was 2.1 (not shown). CT = computed tomography, MR = magnetic resonance, FDG PET = ¹⁸F-fluorodeoxy glucose positron emission tomography.