PURPOSE: PET/CT has a major role in lymphoma imaging, but glycolytic activity in inflammatory processes can reduce specificity. In this study we evaluated restaging PET/CT findings in patients with non-Hodgkin lymphoma (NHL) and fat necrosis.METHODS: We identified 16 patients from 8,819 restaging FDG PET/CT scans with suspicion of or biopsy-proven fat necrosis on PET/CT.RESULTS: All patients had NHL and demonstrated focal FDG-avid nodular change on CT with density higher than that of fat but lower than that of soft tissue. Histological confirmation was obtained in eight patients, with high GLUT-1 staining between necrotic tissue and organizing fat necrosis evident. Uptake resolved in four patients, and surveillance was continuing in four without relapse.CONCLUSION: Although rare, identification of fat necrosis in patients with a solitary FDG-avid nodule after therapy is important and may lead to the avoidance of unnecessary interventions or treatment. Specific features on CT aid identification, whilst follow-up imaging can be helpful as the metabolic abnormality regresses with time.
Adult Aged