PET-positive residual mass in the anterior mediastinum extending into the left supraclavicular region in a patient with nodular sclerosis Hodgkin lymphoma. This patient underwent a restaging PET/CT scan 2 months following treatment with 6 cycles of ABVD. Fused PET/CT images show that the residual mass uptake is clearly greater than that of mediastinal blood pool structures, consistent with persistent disease. This was confirmed by fine needle aspiration and the patient then underwent salvage chemotherapy.