Abstract We present a 24-year-old man with a history of metastatic nasopharyngeal cancer. Despite receiving standard treatments, including surgery, radiotherapy, and chemotherapy, he has shown progression. Consequently, he has been referred to the nuclear medicine department for theranostic purposes. The 99m Tc-FAPI-46 whole-body scan showed tracer uptake in mediastinal large mass, both external lymph nodes and osseous metastases. Treatment with 177 Lu-FAPI-2286 initiated, with subsequent planar scans revealing sustained uptake up to day 10, particularly in the large mediastinal mass. This case indicates promising FAPI-targeted theranostic potential in metastatic nasopharyngeal carcinoma and proper retention of 177 Lu-FAPI-2286 in metastatic lesions.