68Ga-FAPI-04 PET/CT Versus 18F-FDG PET/CT in Malignant Peritoneal Mesothelioma.

An 83-year-old man presented with abdominal pain, vomiting, and bloating. His abdominal CT revealed heterogeneous peritoneal thickening in the lower quadrants, which was more prominent in the pelvic region. 18F-FDG PET/CT performed to locate the primary tumor showed irregular peritoneal and omental thickening with low to moderate FDG uptake. 68Ga-FAPI (fibroblast activation protein-specific inhibitor)-04 PET/CT of the patient, whose primary tumor could not be detected using FDG, showed high radiopharmaceutical uptake in the areas of heterogeneous thickening on peritoneal and serosal surfaces. Peritoneal Tru-Cut biopsy revealed malignant tumoral infiltration indicating mesothelioma. This case showed that 68Ga-FAPI-04 PET/CT could be a promising radiopharmaceutical in the evaluation of peritoneal mesothelioma.