Figure 1. In the upper right thigh, there is a mixed solid and cystic density large mass with enhancement and hypermetabolic activity in the solid components (SUV_max 15.7). There does not appear to be neurovascular involvement.

Figure 2. There are no other hypermetabolic lesions.

In known sarcomas, high SUV correlates with high histological tumour grade. FDG uptake has also been shown to correlate positively with disease progression, and negatively with survival. Benign lesions (such an infection) however, may have uptake comparable to uptake in musculoskeletal sarcomas.

In the assessment of treatment response, morphologic findings alone may not be reliable due to fibrosis, scarring, inflammation and destruction of tissue planes by treatment; thus FDG-PET/CT is also a valuable tool in the assessment of treatment response in musculoskeletal sarcomas.