Fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography (F-18 FDG PET-CT) is the modality of choice for diagnosis, staging, and restaging of many malignancies. The importance of eliminating false positives cannot be underestimated because they can dramatically alter the clinical course. We present a case of benign uptake in the tongue secondary to tardive dyskinesia in a 62-year-old woman referred for staging of ductal carcinoma of the breast who was concurrently receiving oral therapy for schizoaffective disorder. This case emphasizes the importance of direct clinical interview and adequate history taking in the formulation of an appropriate diagnosis.