Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) has proved to be a valuable tool in the restaging of recurrent head and neck cancer. Herein, we report a case of recurrent buccal cancer with false-positive findings of mediastinal lymph node metastases in a FDG PET study. The FDG PET positive lesion was finally proved to be tuberculosis by the mediastinoscope. After salvage surgery, extracapsular spread of neck lymph node was detected. The patient subsequently received concurrent chemoradiotherapy and was disease-free up to 4 months after his salvage therapy. We suggested that a histopathological confirmation of PET findings is mandatory in certain cases before abandoning salvage treatment.