Nodular fasciitis on F-18 FDG PET.

A 36-year-old woman underwent positron emission tomography imaging with F-18-fluorodeoxyglucose (FDG) for evaluation of pulmonary nodules detected in the work-up for persisting dyspnea following respiratory tract infection. The lesions were visible on computed tomography while having only low uptake on the PET images, rendering malignancy less probable. However, increased uptake of FDG was noted in the left groin, where the patient was known to have intramuscular nodular fasciitis. Nodular fasciitis is a benign disorder caused by proliferating fibroblasts and myofibroblasts, which may mimic soft-tissue malignancy clinically, histopathologically, and on imaging procedures