Persistent fluorodeoxyglucose (FDG) uptake in the cervical and mediastinal regions, 3 months after completion of chemo-radiotherapy.

Based on positron emission tomography (PET) alone, no discrimination is possible between residual lymphoma and physiological uptake in muscle and/or brown fat tissue (A). Fusion images located all hot spots to be in brown fat tissue. Based on PET–computed tomography (CT), it was concluded that the patient achieved a complete remission.