Figure 2: A 31-year-old female with a retroperitoneal desmoid tumor (case 3, Table 2; Figure 2) diagnosed in 2006 was treated with imatinib 800 mg daily. The FDG PET prior therapy with imatinib showed an average SUV of 4.2 and an SUVmax of 8.1 (a). After one month of imatinib treatment, the FDG PET demonstrated a decrease of the average SUV to 3.3 (−22%) and of the SUVmax to 6.1 (−25%) (b). Follow-up PET examinations in 2011 and 2012 (c) did not show any pathological FDG uptake. The corresponding conventional MRI documented PR according to RECIST.