A Possible Musculoskeletal Pitfall in 18F-FDG PET: Nodular Fasciitis

A 37-year-old female received a whole-body 18F-FDG PET scan for a purpose of tumor screening. The PET scan revealed a focal FDG-avid lesion at the upper back near the infraspinatus fossa of the right scapula. A malignant lesion was highly suspected. The patient received wide excision and the pathology findings showed an intramuscular well-defined non-encapsulated tumor with a diagnosis of nodular fasciitis. 18F-FDG PET whole-body scan have been reported to be a useful tool in differentiating benign from malignancy. However, some false-positive situations may still interfere with the differentiation. In this case, a benign lesion, nodular fasciitis, can be a pitfall when interpreting an FDG PET image.