Non-Hodgkin's lymphoma of supraclavicular lymph nodes can mimic metastasis of breast cancer during chemotherapy on FDG PET/CT.

A 43-year-old woman who had a history of right mastectomy for breast cancer presented with fever and swelling in the right supraclavicular region during her second course of chemotherapy. An FDG PET/CT was performed to evaluate this patient, which revealed mildly increased FDG activity in the lymph node in the supraclavicular region. A metastatic lesion from the known breast cancer was considered. However, biopsy results demonstrated that the abnormal activity in the right supraclavicular region is due to T-cell lymphoma.