A 44-year-old woman with recurrent parathyroid carcinoma (PTC) presents with moderately elevated parathyroid hormone and ionized calcium levels. Dual-phase Tc-MIBI SPECT study of the neck and chest demonstrated 2 new foci in keeping with neoplastic seeding. A restaging whole-body F-FDG PET/CT showed no evidence of FDG uptake in the region of the MIBI-positive foci or any evidence of distant metastases. The role of F-FDG PET/CT for imaging PTC is still somewhat limited because of the rarity of this disease. We present a case highlighting a potential pitfall for FDG PET in detecting PTC.