Faeze Rabani, Haniye Elahifard, Amin Saber Tanha, Alireza Bari, Emran Askari
We report the case of a 58-year-old man with metastatic epithelioid sarcoma demonstrating an uncommon presentation of expanding tumor volume accompanied by a paradoxically lower SUVmax on 18F-FDG PET/CT. Conversely, 68Ga-FAPI PET/CT demonstrated clear diagnostic superiority, exhibiting intense tracer avidity across established lesions and successfully uncovering multiple new, FDG-occult metastases. This distinct metabolic dissociation highlights a stromal-driven mechanism of tumor invasion. Ultimately, 68Ga-FAPI PET/CT significantly outperforms conventional FDG imaging in delineating total disease burden and detecting clinically occult metastases in this aggressive malignancy.