[68Ga]Ga-FAPI-46 PET/CT and [18F]FDG PET/CT in Polymyalgia Rheumatica, Ovarian Teratoma, and Reactive Peritoneal Lesions: A Case Report

Abstract In this case report, we present a 76-year-old woman who presented with an adnexal mass, ascites, and peritoneal lesions, all features highly suspicious for ovarian cancer. The patient was enrolled in a clinical trial evaluating the diagnostic performance and clinical value of [68Ga]Ga-fibroblast activation protein inhibitor-46 ([68Ga]Ga-FAPI-46) PET/CT, a novel PET tracer that has demonstrated promising results in ovarian cancer. The preoperative [18F]Fluorodeoxyglucose ([18F]FDG) PET/CT and [68Ga]Ga-FAPI-46 PET/CT showed up to moderate tracer uptake in the ovarian tumor and peritoneal lesions; however, final histopathology revealed a benign teratoma and peritoneal reactive changes. Furthermore, the patient had a history of Polymyalgia Rheumatica (PMR), and [18F]FDG PET/CT showed classic findings of PMR. [68Ga]Ga-FAPI-46 PET/CT revealed similar results, but with even higher tracer accumulation in affected locations. This case is the first to demonstrate the potential of [68Ga]Ga-FAPI-46 PET/CT in PMR.