Unusual Metastasis of Signet-Ring Cell Gastric Cancer That Could Not Be Detected With 18F-FDG PET But With 68Ga-FAPI PET/CT.

A 70-year-old man who was scheduled for surgery because of the recurrence of gastric cancer was referred to our clinic preoperatively. The patient underwent a comprehensive evaluation through 18F-FDG and 68Ga-FAPI (68Ga-labeled FAP inhibitors) PET/CT scans. The 68Ga-FAPI PET/CT scan was particularly valuable in this case because of its ability to detect recurrent mass lesions and identify unusual metastatic sites compared with the 18F-FDG PET/CT scan.