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 F-18-FDG and Ga-68-FAPI (68Ga-labeled FAP inhibitors) PET/CT scans. The Ga-68-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 F-18-FDG PET/CT scan.