68Ga-FAPI-04 PET/CT Imaging for Fibrous Dysplasia of the Bone.

68Ga-labeled quinoline-based fibroblast activation protein inhibitors (68Ga-FAPIs) are promising agents for tumor imaging. However, some nonneoplastic lesions can also cause increased FAPI uptake. We report a case of a patient with polyostotic fibrous dysplasia who showed widespread and intense metabolic activity on 68Ga-FAPI PET/CT. Physicians should be aware that fibrous dysplasia can also cause elevated FAPI activity.