Figure 24. 46-year-old female patient with chondrosarcoma of the right maxillary sinus.

a) Preoperative axial T2w image demonstrates an inhomogeneous tumor with discrete infiltration of the surrounding soft tissue.

b) Contrast-enhanced T1w follow-up image demonstrating extensive scar formation which cannot be differentiated from recurrent tumor.

c) FDG-PET/CT performed the next day demonstrating increased metabolism within the scar formation, indicating recurrent disease, which was confirmed by surgery.