A 35-year-old woman, already treated with surgery, chemotherapy, and radiotherapy for a ductal carcinoma of the left breast, underwent an ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) scan for an increase of the serum markers carcinoembryonic antigen (CEA) and cancer antigen 15.3 (CA 15.3). The scan showed multiple FDG-avid lesions in the liver and bone. The images also detected two areas of uptake in the dorsal and lumbar spinal cord, which were suspicious for metastases; magnetic resonance imaging (MRI) confirmed these lesions.